Methods for the Production of alpha,beta-Unsaturated Carboxylic Acids and Salts Thereof

ABSTRACT

Processes for producing an α,β-unsaturated carboxylic acid, such as acrylic acid, or a salt thereof, using treated solid oxides are disclosed. The treated solid oxides can be calcined solid oxides, metal-treated solid oxides, or metal-treated chemically-modified solid oxides, illustrative examples of which can include sodium-treated alumina, calcium-treated alumina, zinc-treated alumina, sodium-treated sulfated alumina, sodium-treated fluorided silica-coated alumina, and similar materials.

REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part application of co-pendingU.S. patent application Ser. No. 14/509,082, filed on Oct. 8, 2014, thedisclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

The majority of industrially synthesized chemical compounds are preparedfrom a limited set of precursors, whose sources are ultimately fossilfuels. It would be beneficial to use a renewable resource, such ascarbon dioxide, which is a non-toxic, abundant, and economical C₁synthetic unit. The coupling of carbon dioxide and olefins holdstremendous promise as one could envision the direct preparation ofacrylates and carboxylic acids through this method. Currently, acrylicacid is produced via a two-stage oxidation of propylene. The productionof acrylic acid directly from carbon dioxide and ethylene wouldrepresent a significant improvement due to the greater availability ofethylene and carbon dioxide versus propylene, the use of a renewablematerial (CO₂) in the synthesis, and the replacement of the two-stepoxygenation process currently being practiced. Accordingly, it is tothese ends that the present invention is directed.

SUMMARY OF THE INVENTION

Processes for producing an α,β-unsaturated carboxylic acid, or a saltthereof, are disclosed herein. These processes represent an improvementover homogeneous processes that result in poor yields and havechallenging separation/isolation procedures, due in part to the reactionbeing conducted in an organic solvent, making isolation of the desiredα,β-unsaturated carboxylic acid (e.g., acrylic acid) difficult. Incontrast, the processes disclosed herein utilize a solid promoter (orsolid activator, such as a treated solid oxide), providing aheterogeneous system that has a distinct advantage in ease of separationof the desired product from the catalytic promoter. Moreover, the solidpromoters can result in surprisingly high yields of the desired acrylateor α,β-unsaturated carboxylic acid, such as acrylic acid.

In accordance with aspects of the present invention, one such processfor producing an α,β-unsaturated carboxylic acid, or a salt thereof, cancomprise:

(1) contacting

-   -   (a) a metallalactone;    -   (b) a diluent; and    -   (c) a solid promoter (e.g., a treated solid oxide);

(2) forming an adduct of an α,β-unsaturated carboxylic acid adsorbedonto the solid promoter; and

(3) treating the adduct adsorbed onto the solid promoter to produce theα,β-unsaturated carboxylic acid, or the salt thereof.

In another aspect of this invention, a process for producing anα,β-unsaturated carboxylic acid, or a salt thereof, is provided, and inthis aspect, the process can comprise:

(I) contacting

-   -   (i) a transition metal-ligand complex;    -   (ii) an olefin;    -   (iii) carbon dioxide (CO₂);    -   (iv) a diluent; and    -   (v) a solid promoter (e.g., a treated solid oxide); and

(II) forming the α,β-unsaturated carboxylic acid, or the salt thereof.

Yet, in another aspect of this invention, a process for performing ametallalactone elimination reaction is provided, and in this aspect, theprocess can comprise:

(1) contacting

-   -   (a) a metallalactone;    -   (b) a diluent; and    -   (c) a solid promoter (e.g., a treated solid oxide); and

(2) forming an α,β-unsaturated carboxylic acid, or a salt thereof.

In these and other aspects, the processes disclosed herein can be usedto produce, for instance, acrylic acid or a salt thereof.

Both the foregoing summary and the following detailed descriptionprovide examples and are explanatory only. Accordingly, the foregoingsummary and the following detailed description should not be consideredto be restrictive. Further, features or variations may be provided inaddition to those set forth herein. For example, certain aspects may bedirected to various feature combinations and sub-combinations describedin the detailed description.

DEFINITIONS

To define more clearly the terms used herein, the following definitionsare provided. Unless otherwise indicated, the following definitions areapplicable to this disclosure. If a term is used in this disclosure butis not specifically defined herein, the definition from the IUPACCompendium of Chemical Terminology, 2^(nd) Ed (1997) can be applied, aslong as that definition does not conflict with any other disclosure ordefinition applied herein, or render indefinite or non-enabled any claimto which that definition is applied. To the extent that any definitionor usage provided by any document incorporated herein by referenceconflicts with the definition or usage provided herein, the definitionor usage provided herein controls.

While compositions and methods are described in terms of “comprising”various components or steps, the compositions and methods can also“consist essentially of” or “consist of” the various components orsteps, unless stated otherwise. For example, a step in certain processesconsistent with the present invention can contact components comprisinga metallalactone, a diluent, and a treated solid oxide; alternatively,can contact components consisting essentially of a metallalactone, adiluent, and a treated solid oxide; or alternatively, can contactcomponents consisting of a metallalactone, a diluent, and a treatedsolid oxide.

The terms “a,” “an,” and “the” are intended to include pluralalternatives, e.g., at least one. For instance, the disclosure of “asolid promoter,” “a treated solid oxide,” or “a diluent,” is meant toencompass one, or mixtures or combinations of more than one, solidpromoter, treated solid oxide, or diluent, respectively, unlessotherwise specified.

Generally, groups of elements are indicated using the numbering schemeindicated in the version of the periodic table of elements published inChemical and Engineering News, 63(5), 27, 1985. In some instances, agroup of elements can be indicated using a common name assigned to thegroup; for example, alkali metals for Group 1 elements, alkaline earthmetals for Group 2 elements, transition metals for Group 3-12 elements,and halogens or halides for Group 17 elements.

The term “hydrocarbon” refers to a compound containing only carbon andhydrogen. Other identifiers may be utilized to indicate the presence ofparticular groups in the hydrocarbon, for instance, a halogenatedhydrocarbon indicates the presence of one or more halogen atomsreplacing an equivalent number of hydrogen atoms in the hydrocarbon.

As used herein, the term “α,β-unsaturated carboxylic acid” and itsderivatives refer to a carboxylic acid having a carbon atom of acarbon-carbon double bond attached to the carbonyl carbon atom (thecarbon atom bearing the double bonded oxygen atom). Optionally, theα,β-unsaturated carboxylic acid may contain other functional groupsand/or heteroatoms.

For any particular compound or group disclosed herein, any name orstructure presented is intended to encompass all conformational isomers,regioisomers, stereoisomers, and mixtures thereof that may arise from aparticular set of substituents, unless otherwise specified. The name orstructure also encompasses all enantiomers, diastereomers, and otheroptical isomers (if there are any) whether in enantiomeric or racemicforms, as well as mixtures of stereoisomers, as would be recognized by askilled artisan, unless otherwise specified. For example, a generalreference to pentane includes n-pentane, 2-methyl-butane, and2,2-dimethylpropane; and a general reference to a butyl group includes an-butyl group, a sec-butyl group, an iso-butyl group, and a t-butylgroup.

Various numerical ranges are disclosed herein. When a range of any typeis disclosed or claimed, the intent is to disclose or claim individuallyeach possible number that such a range could reasonably encompass,including end points of the range as well as any sub-ranges andcombinations of sub-ranges encompassed therein, unless otherwisespecified. Moreover, all numerical end points of ranges disclosed hereinare approximate. As a representative example, it is disclosed in anaspect of the invention that one or more steps in the processes of thisinvention can be conducted at a temperature in a range from 10° C. to75° C. This range should be interpreted as encompassing temperatures ina range from “about” 10° C. to “about” 75° C.

The term “substituted” when used to describe a group, for example, whenreferring to a substituted analog of a particular group, is intended todescribe the compound or group wherein any non-hydrogen moiety formallyreplaces hydrogen in that group or compound, and is intended to benon-limiting. A compound or group can also be referred to herein as“unsubstituted” or by equivalent terms such as “non-substituted,” whichrefers to the original group or compound. Unless otherwise specific,“substituted” is intended to be non-limiting and include inorganicsubstituents or organic substituents as specified and as understood byone of ordinary skill in the art.

The terms “contact product,” “contacting,” and the like, are used hereinto describe compositions and methods wherein the components are combinedor contacted together in any order, in any manner, and for any length oftime, unless otherwise specified. For example, the components can becontacted by blending or mixing. Further, unless otherwise specified,the contacting of any component can occur in the presence or absence ofany other component of the compositions and methods described herein.Combining additional materials or components can be done by any suitablemethod. Further, the term “contact product” includes mixtures, blends,solutions, slurries, reaction products, and the like, or combinationsthereof. Although “contact product” can, and often does, includereaction products, it is not required for the respective components toreact with one another. Similarly, the term “contacting” is used hereinto refer to materials which can be blended, mixed, slurried, dissolved,reacted, treated, or otherwise combined or contacted in some othermanner.

Although any methods and materials similar or equivalent to thosedescribed herein can be used in the practice or testing of theinvention, the typical methods and materials are herein described.

All publications and patents mentioned herein are incorporated herein byreference for the purpose of describing and disclosing, for example, theconstructs and methodologies that are described in the publications,which might be used in connection with the presently describedinvention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed generally to methods for formingα,β-unsaturated carboxylic acids, or salts thereof. An illustrativeexample of a suitable α,β-unsaturated carboxylic acid is acrylic acid.

As disclosed herein, the heterogeneous processes of this invention canprovide a distinct advantage over homogeneous systems in the ease ofseparation (e.g., solid-liquid separation techniques) of the desiredreaction product from the solid catalytic promoter (e.g., the treatedsolid oxide). Moreover, and while not wishing to be bound by thefollowing theory, it is believed that the processes of this inventionare also advantageous in that an additional or auxiliary liquid base(e.g., an alkoxide, hydride, or amine) is not needed to perform thedisclosed processes. Further, a transition metal complex that iscovalently bound or immobilized on a solid support (e.g., with a linkingmoiety) is not needed to perform the disclosed processes. Further, aheterogeneous base comprising an organic basic moiety that is covalentlybound or immobilized on a solid support (e.g., with a linking moiety) isnot needed to perform the disclosed processes. Further, a consumableheterogeneous alkalinity reservoir (e.g., NaH) with an organic basedissolved in a reaction media is not needed to perform the disclosedprocesses. And lastly, an aryloxide (e.g., a fluorophenolate) is notneeded to perform the disclosed processes.

Moreover, and while not wishing to be bound by the following theory, itis believed that the combined acid and base functionality (e.g., thecombined Lewis acid and Brønsted base characteristics) of certaintreated solid oxides disclosed herein may result in the surprisinglyhigh yields in both the metallalactone elimination reactions and thecarboxylic acid forming reactions.

Solid Promoters

Generally, the solid promoter used in the processes disclosed herein cancomprise (or consist essentially of, or consist of) a solid oxide, aclay or pillared clay, or combinations thereof. For instance, it iscontemplated that mixtures or combinations of two or more solidpromoters can be employed in certain aspects of the invention.Generally, the term solid promoter is used interchangeably herein withsolid activator.

In accordance with one aspect, the solid promoter can comprise a basicpromoter, for instance, a solid promoter that can act as a base.Representative and non-limiting examples of basic promoters can includealumina, titania, zirconia, magnesia, boria, calcia, zinc oxide,silica-alumina, silica-coated alumina, silica-titania, silica-zirconia,silica-magnesia, alumina-titania, alumina-zirconia, zinc-aluminate,alumina-boria, silica-boria, aluminum phosphate, aluminophosphate,aluminophosphate-silica, magnesium aluminate, titania-zirconia, and thelike, as well as combinations thereof. In accordance with anotheraspect, the solid promoter can comprise a Lewis acid promoter.Representative and non-limiting examples of Lewis acid promoters caninclude silica, alumina, titania, zirconia, magnesia, boria, calcia,zinc oxide, silica-alumina, silica-coated alumina, silica-titania,silica-zirconia, silica-magnesia, alumina-titania, alumina-zirconia,zinc-aluminate, alumina-boria, silica-boria, aluminum phosphate,aluminophosphate, aluminophosphate-silica, magnesium aluminate,titania-zirconia, and the like, as well as combinations thereof. Inaccordance with yet another aspect, the solid promoter can comprise aBrønsted base promoter. Representative and non-limiting examples ofBrønsted base promoters can include alumina, titania, zirconia,magnesia, boria, calcia, zinc oxide, silica-coated alumina,silica-titania, silica-zirconia, silica-magnesia, alumina-titania,alumina-zirconia, zinc-aluminate, alumina-boria, silica-boria, aluminumphosphate, aluminophosphate, aluminophosphate-silica, magnesiumaluminate, titania-zirconia, and the like, as well as combinationsthereof. In accordance with still another aspect, the solid promoter cancomprise a Brønsted base and Lewis acid promoter. Representative andnon-limiting examples of Brønsted base and Lewis acid promoters caninclude alumina, titania, zirconia, magnesia, boria, calcia, zinc oxide,silica-coated alumina, silica-titania, silica-zirconia, silica-magnesia,alumina-titania, alumina-zirconia, zinc-aluminate, alumina-boria,silica-boria, aluminum phosphate, aluminophosphate,aluminophosphate-silica, magnesium aluminate, titania-zirconia, and thelike, as well as combinations thereof.

Consistent with aspects of this invention, the solid promoter cancomprise (or consist essentially of, or consist of) a solid oxide.Generally, the solid oxide can comprise oxygen and one or more elementsselected from Group 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15of the periodic table, or comprise oxygen and one or more elementsselected from the lanthanide or actinide elements (See: Hawley'sCondensed Chemical Dictionary, 11^(th) Ed., John Wiley & Sons, 1995;Cotton, F. A., Wilkinson, G., Murillo, C. A., and Bochmann, M., AdvancedInorganic Chemistry, 6^(th) Ed., Wiley-Interscience, 1999). For exampleand not limited thereto, the solid oxide can comprise oxygen and anelement, or elements, selected from Al, B, Be, Bi, Cd, Co, Cr, Cu, Fe,Ga, La, Mn, Mo, Ni, Sb, Si, Sn, Sr, Th, Ti, V, W, P, Y, Zn, Zr, Na, K,Cs, Ca, Ba, and Li.

Illustrative examples of solid oxides that can be used as solidpromoters as described herein can include, but are not limited to,Al₂O₃, B₂O₃, BeO, Bi₂O₃, BaO, MgO, CaO, CdO, Ce₂O_(3,) Co₃O₄, Cr₂O₃,CuO, Fe₂O₃, Ga₂O₃, K₂O, La₂O₃, Mn₂O₃, MoO₃, Na₂O, NiO, P₂O₅, Sb₂O₅,SiO₂, SnO₂, SrO, ThO₂, TiO₂, V₂O₅, WO₃, Y₂O₃, ZnO, ZrO₂, and the like,including mixed oxides thereof, and combinations thereof. In addition,solid oxide is meant to encompass carbonates and hydroxides of the aboveelements, either alone or in combination. Illustrative and non-limitingexamples of carbonates include sodium carbonate, sodium bicarbonate,potassium carbonate, cesium carbonate, and the like.

In an aspect, the solid oxide can comprise silica, alumina, titania,zirconia, magnesia, boria, calcia, zinc oxide, silica-alumina,silica-coated alumina, silica-titania, silica-zirconia, silica-magnesia,alumina-titania, alumina-zirconia, zinc-aluminate, alumina-boria,silica-boria, aluminum phosphate, aluminophosphate,aluminophosphate-silica, magnesium aluminate, titania-zirconia, and thelike, or a combination thereof alternatively, silica; alternatively,alumina; alternatively, titania; alternatively, zirconia; alternatively,magnesia; alternatively, boria; alternatively, calcia; alternatively,zinc oxide; alternatively, silica-alumina; alternatively, silica-coatedalumina; alternatively, silica-titania; alternatively, silica-zirconia;alternatively, silica-magnesia; alternatively, alumina-titania;alternatively, alumina-zirconia; alternatively, zinc-aluminate;alternatively, alumina-boria; alternatively, silica-boria;alternatively, aluminum phosphate; alternatively, aluminophosphate;alternatively, aluminophosphate-silica; alternatively, magnesiumaluminate; or alternatively, titania-zirconia. In another aspect, thesolid oxide can comprise magnesium aluminate, calcium aluminate, zincaluminate, zirconium aluminate, sodium aluminate, magnesium zirconiumoxide, sodium zirconium oxide, calcium zirconium oxide, lanthanumchromium oxide, barium titanium oxide, and the like, or a combinationthereof; alternatively, magnesium aluminate; alternatively, calciumaluminate; alternatively, zinc aluminate; alternatively, zirconiumaluminate; alternatively, sodium aluminate; alternatively, magnesiumzirconium oxide; alternatively, sodium zirconium oxide; alternatively,calcium zirconium oxide; alternatively, lanthanum chromium oxide; oralternatively, barium titanium oxide. Various methods for producingsuitable solid oxides and mixed solid oxides, such as co-gelling, dopingor impregnating are disclosed in, for example, U.S. Pat. Nos. 6,107,230,6,165,929, 6,294,494, 6,300,271, 6,316,553, 6,355,594, 6,376,415,6,388,017, 6,391,816, 6,395,666, 6,524,987, 6,548,441, 6,548,442,6,576,583, 6,613,712, 6,632,894, 6,667,274, 6,750,302, 7,294,599,7,601,665, 7,884,163, and 8,309,485, which are incorporated herein byreference in their entirety. Other suitable processes and procedures forpreparing solid oxides that can be used as solid promoters are wellknown to those of skill in the art.

As disclosed herein, the solid oxide can comprise silica-coated alumina,as described in U.S. Pat. No. 7,884,163 (e.g., Sasol Siral® 28 or SasolSiral® 40). Such silica-coated alumina solid oxide materials often arealumina-rich, with the weight ratio of alumina to silica(alumina:silica) in the silica-coated alumina typically falling in arange from 1.05:1 to 50:1, from 1.1:1 to 25:1, from 1.2:1 to 12:1, from1.2:1 to 4:1, from 1.3:1 to 6:1, or from 1.3:1 to 3:1.

Consistent with aspects of this invention, the solid promoter cancomprise (or consist essentially of, or consist of) a clay or a pillaredclay. The clay or pillared clay materials that can be employed as asolid promoter in the disclosed processes can encompass clay materialseither in their natural state or that have been treated with variousions by wetting, ion exchange, pillaring, or other processes. In someaspects, the clay or pillared clay material can comprise clays that havebeen ion exchanged with large cations, including polynuclear, highlycharged metal complex cations. In other aspects, the clay or pillaredclay material can comprise clays that have been ion exchanged withsimple salts, including, but not limited to, salts of Al(III), Fe(II),Fe(III), and Zn(II) with ligands such as halide, acetate, sulfate,nitrate, nitrite, and the like.

In another aspect, the clay or pillared clay material can comprise apillared clay. The term “pillared clay” can be used to refer to claymaterials that have been ion exchanged with large, typicallypolynuclear, highly charged metal complex cations. Examples of such ionsinclude, but are not limited to, Keggin ions which can have charges suchas 7+, various polyoxometallates, and other large ions. Thus, the termpillaring generally refers to a simple exchange reaction in which theexchangeable cations of a clay material can be replaced with large,highly charged ions, such as Keggin ions. These polymeric cations arethen immobilized within the interlayers of the clay, and when calcinedcan be converted to metal oxide “pillars,” effectively supporting theclay layers as column-like structures. Thus, once the clay has beendried and calcined to produce the supporting pillars between claylayers, the expanded lattice structure can be maintained and theporosity can be enhanced. The resulting pores can vary in shape and sizeas a function of the pillaring material and the parent clay materialused, among other variables. Examples of pillaring and pillared claysare found in: T. J. Pinnavaia, Science 220 (4595), 365-371 (1983); J. M.Thomas, Intercalation Chemistry, (S. Whittington and A. Jacobson, eds.)Ch. 3, pp. 55-99, Academic Press, Inc., (1972); U.S. Pat. No. 4,452,910;U.S. Pat. No. 5,376,611; and U.S. Pat. No. 4,060,480; the disclosures ofwhich are incorporated herein by reference in their entirety.

In some aspects, the clay or pillared clay can comprise montmorillonite,bentonite, nontronite, hectorite, halloysite, vermiculite, mica,fluoromica, chlorite, sepiolite, attapulgite, palygorskite, illite,saponite, allophone, smectite, kaolinite, pyrophyllite, and the like, orany combination thereof. In other aspects, the clay or pillared clay cancomprise montmorillonite; alternatively, bentonite; alternatively,nontronite; alternatively, hectorite; alternatively, halloysite;alternatively, vermiculite; alternatively, mica; alternatively,fluoromica; alternatively, chlorite; alternatively, sepiolite;alternatively, attapulgite; alternatively, palygorskite; alternatively,illite; alternatively, saponite; alternatively, allophone;alternatively, smectite; alternatively, kaolinite; or alternatively,pyrophyllite.

In accordance with an aspect of this invention, the solid promoter cancomprise silica, alumina, silica-alumina, aluminum phosphate,alumina-boria, silica-magnesia, silica-titania, zirconia, magnesia,magnesium aluminate, sepiolite, titania, palygorskite, montmorillonite,talc, kaolinite, halloysite, pyrophyllite, and the like, as well ascombinations thereof. In accordance with another aspect, the solidpromoter can comprise silica, alumina, silica-alumina, aluminumphosphate, alumina-boria, silica-magnesia, silica-titania, zirconia,magnesia, magnesium aluminate, titania, and the like, as well ascombinations thereof. In accordance with yet another aspect, the solidpromoter can comprise sepiolite, palygorskite, montmorillonite, talc,kaolinite, halloysite, pyrophyllite, and the like, as well ascombinations thereof. In accordance with still another aspect, the solidpromoter can comprise alumina, zirconia, magnesia, magnesium aluminate,sepiolite, and the like, as well as combinations thereof; alternatively,alumina; alternatively, zirconia; alternatively, magnesia;alternatively, magnesium aluminate; or alternatively, sepiolite.

The solid promoters contemplated herein can have any suitable surfacearea, pore volume, and particle size, as would be recognized by those ofskill in the art. For instance, the solid promoter can have a porevolume in a range from 0.1 mL/g to 2.5 mL/g, or alternatively, from 0.5mL/g to 2.5 mL/g. In a further aspect, the promoter can have a porevolume from 1 mL/g to 2.5 mL/g, or from 0.1 mL/g to 1.5 mL/g.Alternatively, the pore volume can be from 0.1 mL/g to 1.0 mL/g, or from0.2 mL/g to 1.0 mL/g. Additionally, or alternatively, the solid promotercan have a BET surface area in a range from 10 m²/g to 750 m²/g;alternatively, from 100 m²/g to 750 m²/g; alternatively, from 100 m²/gto 500 m²/g; or alternatively, from 30 m²/g to 200 m²/g. In a furtheraspect, the solid promoter can have a surface area of from 20 m²/g to500 m²/g, from 30 m²/g to 350 m²/g, from 100 m²/g to 400 m²/g, from 200m²/g to 450 m²/g, or from 150 m²/g to 350 m²/g. The average particlesize of the solid promoter can vary greatly depending upon the processspecifics, however, average particle sizes in the range of from 5microns to 500 microns, from 10 microns to 250 microns, or from 25microns to 200 microns, are often employed. Alternatively, 1/8 inch to1/4 inch pellets or beads can be used.

Prior to use, these solid promoters can be calcined. The calcining stepcan be conducted at a variety of temperatures and time periods, and in avariety of atmospheres (an inert atmosphere, an oxidizing atmosphere, areducing atmosphere). For instance, the calcining step can be conductedat a peak calcining temperature in a range from 150° C. to 1000° C.;alternatively, from 250° C. to 1000° C.; alternatively, from 200° C. to750° C.; alternatively, from 200° C. to 600° C.; alternatively, from250° C. to 950° C.; alternatively, from 250° C. to 750° C.;alternatively, from 400° C. to 700° C.; alternatively, from 300° C. to650° C.; or alternatively, from 400° C. to 600° C. In these and otheraspects, these temperature ranges also are meant to encompasscircumstances where the calcining step is conducted at a series ofdifferent temperatures (e.g., an initial calcining temperature, a peakcalcining temperature), instead of at a single fixed temperature,falling within the respective ranges. For instance, the calcining stepcan start at an initial calcining temperature, and subsequently, thetemperature of the calcining step can be increased to the peak calciningtemperature, for example, a peak calcining temperature in a range from500° C. to 1000° C., or from 250° C. to 750° C.

The duration of the calcining step is not limited to any particularperiod of time. Hence, the calcining step can be conducted, for example,in a time period ranging from as little as 15-45 minutes to as long as12-24 hours, or more. The appropriate calcining time can depend upon,for example, the initial/peak calcining temperature, and the atmosphereunder which calcining is conducted, among other variables. Generally,however, the calcining step can be conducted in a time period that canbe in a range from 45 minutes to 18 hours, such as, for example, from 45minutes to 15 hours, from 1 hour to 12 hours, from 2 hours to 10 hours,from 3 hours to 10 hours, or from 4 hours to 10 hours.

In accordance with the present invention, the solid promoter cancomprise (or consist essentially of, or consist of) a treated solidoxide. For example, the treated solid oxide can be a calcined solidoxide, a metal-treated solid oxide, a metal-treated chemically-modifiedsolid oxide, or a combination thereof. The solid oxide of the treatedsolid oxide can be any suitable solid oxide, or any solid oxidedisclosed herein, such as alumina, silica-alumina, silica-coatedalumina, aluminophosphate, sodium carbonate, or sodium bicarbonate, andthe like. Combinations of more than one treated solid oxide, if desired,can be used in the processes of this invention. In a particular aspectof this invention, the solid oxide can comprise alumina, silica-alumina,silica-coated alumina, or a mixture thereof.

Consistent with aspects of this invention, the treated solid oxide canbe characterized as a Lewis acid. Additionally or alternatively, thetreated solid oxide can be characterized as a Brønsted base.Accordingly, in some aspects, the treated solid oxide can becharacterized as both a Brønsted base and a Lewis acid.

As disclosed herein, the treated solid oxide can be a calcined solidoxide. Generally, prior to step (1) or step (I) of the processes of thisinvention, the treated solid oxide can be formed by calcining at anysuitable temperature, or at a temperature in any range disclosed herein.Calcining temperatures in a range from 150° C. to 1000° C., from 200° C.to 750° C., or from 200° C. to 600° C., often can be used. Illustrativeand non-limiting examples of treated solid oxides in this aspect of theinvention can include calcined sodium carbonate, calcined sodiumbicarbonate, calcined potassium carbonate, calcined cesium carbonate,calcined alumina, calcined zirconia, calcined magnesia, and the like, aswell as combinations thereof.

As disclosed herein, the treated solid oxide can be a metal-treatedsolid oxide. The term “metal-treated” solid oxide is meant to encompasssolid oxides that may be described alternatively as one or more ofmetal-containing solid oxides, metal-impregnated solid oxides,metal-modified solid oxides, and/or metal-enriched solid oxides.Generally, prior to step (1) or step (I) of the processes of thisinvention, the metal-treated solid oxide can be produced by a processcomprising contacting any suitable solid oxide and any suitablemetal-containing compound and calcining. The calcining can be performedconcurrently with this contacting step and/or subsequent to thiscontacting step, and can be performed at any suitable conditions or atany calcining conditions disclosed herein.

The metal-treated solid oxide can comprise an alkali metal, an alkalineearth metal, a transition metal, or any combination thereof (e.g., atransition metal and an alkali metal). When the metal-treated solidoxide comprises an alkali metal, the treated solid oxide can be referredto as an alkali metal-treated solid oxide, and the alkali metal oftencomprises sodium, potassium, or cesium, either singly or in combination.Illustrative and non-limiting examples of alkali-metal treated solidoxides can include sodium-treated alumina, potassium-treated alumina,cesium-treated alumina, sodium-treated aluminophosphate, and the like,as well as combinations thereof. When the metal-treated solid oxidecomprises an alkaline earth metal, the treated solid oxide can bereferred to as an alkaline earth metal-treated solid oxide, and thealkaline earth metal often comprises magnesium, calcium, or barium,either singly or in combination. Illustrative and non-limiting examplesof alkaline earth metal-treated solid oxides can includemagnesium-treated alumina, calcium-treated alumina, barium-treatedalumina, and the like, as well as combinations thereof. When themetal-treated solid oxide comprises a transition metal, the treatedsolid oxide can be referred to as a transition metal-treated solidoxide, and the transition metal can comprise any transition metaldisclosed herein, such as titanium, zirconium, hafnium, tungsten, orzinc, and either singly or in combination. Illustrative and non-limitingexamples of transition metal-treated solid oxides can includezinc-treated alumina, zirconium-treated alumina, sodium-tungsten-treatedalumina, and the like, as well as combinations thereof.

As disclosed herein, the treated solid oxide can be a metal-treatedchemically-modified solid oxide. Generally, prior to step (1) or step(I) of the processes of this invention, the metal-treatedchemically-modified solid oxide can be produced by a process comprisingcontacting any suitable solid oxide and any electron-withdrawing anionand calcining (concurrently and/or subsequently) to form thechemically-modified solid oxide, and then contacting thechemically-modified solid oxide with any suitable metal-containingcompound. Optionally, a further calcining step can be used.

The metal-treated chemically-modified solid oxide can comprise an alkalimetal, an alkaline earth metal, a transition metal, or any combinationthereof (e.g., a transition metal and an alkali metal). When themetal-treated chemically-modified solid oxide comprises an alkali metal,the treated solid oxide can be referred to as an alkali metal-treatedchemically-modified solid oxide, and the alkali metal often comprisessodium, potassium, or cesium, either singly or in combination. When themetal-treated chemically-modified solid oxide comprises an alkalineearth metal, the treated solid oxide can be referred to as an alkalineearth metal-treated chemically-modified solid oxide, and the alkalineearth metal often comprises magnesium, calcium, or barium, either singlyor in combination. When the metal-treated chemically-modified solidoxide comprises a transition metal, the treated solid oxide can bereferred to as a transition metal-treated chemically-modified solidoxide, and the transition metal can comprise any transition metaldisclosed herein, such as titanium, zirconium, hafnium, tungsten, orzinc, and either singly or in combination. Illustrative and non-limitingexamples of metal-treated chemically-modified solid oxides can includesodium-treated chlorided alumina, sodium-treated sulfated alumina,sodium-treated sulfated silica-coated alumina, sodium-treated fluoridedsilica-coated alumina, sodium-treated fluorided silica-alumina,sodium-treated fluorided-chlorided silica-coated alumina, and the like,as well as combinations thereof.

When present, any metal in a metal-treated solid oxide or ametal-treated chemically-modified solid oxide often is present in anamount of at least 0.5 wt. %, or at least 1 wt. %. For instance, themetal-treated solid oxide (or metal-treated chemically-modified solidoxide) generally can contain from 1 to 30 wt. % of the metal, based onthe weight of the metal-treated solid oxide (or metal-treatedchemically-modified solid oxide). In particular aspects provided herein,the metal-treated solid oxide (or metal-treated chemically-modifiedsolid oxide) can contain from 1 to 25 wt. %, from 2 to 30 wt. %, from 2to 25 wt. %, from 5 to 30 wt. %, from 5 to 25 wt. %, from 3 to 15 wt. %,from 5 to 12 wt. %, or from 6 to 18 wt. %, of the metal, based on thetotal weight of the metal-treated solid oxide (or metal-treatedchemically-modified solid oxide).

In the processes disclosed herein, any suitable chemically-modifiedsolid oxide can be employed in this invention, whether onechemically-modified solid oxide or a mixture or combination of two ormore different chemically-modified solid oxides. The chemically-modifiedsolid oxide can comprise a solid oxide contacted with anelectron-withdrawing anion, for instance, any solid oxide and anyelectron-withdrawing anion disclosed herein. In an aspect, thechemically-modified solid oxide can comprise a solid oxide contactedwith an electron-withdrawing anion, the solid oxide containing aLewis-acidic metal ion. Non-limiting examples of suitablechemically-modified solid oxides are disclosed in, for instance,

U.S. Pat. Nos. 7,294,599, 7,601,665, 7,884,163, 8,309,485, 8,623,973,8,703,886, and 9,023,959, incorporated herein by reference in theirentirety.

The electron-withdrawing component used to treat or modify the solidoxide can be any component that can increase the Lewis or Brønstedacidity of the solid oxide upon treatment (as compared to the solidoxide that is not treated with at least one electron-withdrawing anion).According to one aspect, the electron-withdrawing component can be anelectron-withdrawing anion derived from a salt, an acid, or othercompound, such as a volatile organic compound, that serves as a sourceor precursor for that anion. Examples of electron-withdrawing anions caninclude, but are not limited to, sulfate, bisulfate, fluoride, chloride,bromide, iodide, fluorosulfate, fluoroborate, phosphate,fluorophosphate, trifluoroacetate, triflate, fluorozirconate,fluorotitanate, phospho-tungstate, tungstate, and molybdate, includingmixtures and combinations thereof. In addition, other ionic or non-ioniccompounds that serve as sources for these electron-withdrawing anionsalso can be employed. It is contemplated that the electron-withdrawinganion can be, or can comprise, fluoride, chloride, bromide, phosphate,triflate, bisulfate, or sulfate, or any combination thereof, in someaspects provided herein. In other aspects, the electron-withdrawinganion can comprise sulfate, bisulfate, fluoride, chloride, bromide,iodide, fluorosulfate, fluoroborate, phosphate, fluorophosphate,trifluoroacetate, triflate, fluorozirconate, fluorotitanate, orcombinations thereof. Yet, in other aspects, the electron-withdrawinganion can comprise sulfate, fluoride, chloride, or combinations thereofalternatively, sulfate; alternatively, fluoride and chloride; oralternatively, fluoride.

The chemically-modified solid oxide generally can contain from 1 to 30wt. % of the electron-withdrawing anion, based on the weight of thechemically-modified solid oxide. In particular aspects provided herein,the chemically-modified solid oxide can contain from 1 to 20 wt. %, from2 to 20 wt. %, from 3 to 20 wt. %, from 2 to 15 wt. %, from 3 to 15 wt.%, from 3 to 12 wt. %, from 4 to 10 wt. %, or from 5 to 9 wt. %, of theelectron-withdrawing anion, based on the total weight of thechemically-modified solid oxide.

In one aspect, the chemically-modified solid oxide can comprisefluorided alumina, chlorided alumina, bromided alumina, sulfatedalumina, fluorided silica-alumina, chlorided silica-alumina, bromidedsilica-alumina, sulfated silica-alumina, fluorided silica-zirconia,chlorided silica-zirconia, bromided silica-zirconia, sulfatedsilica-zirconia, fluorided silica-titania, fluorided silica-coatedalumina, fluorided-chlorided silica-coated alumina, sulfatedsilica-coated alumina, or phosphated silica-coated alumina, as well asany mixture or combination thereof. In another aspect, thechemically-modified solid oxide employed in the processes describedherein can be, or can comprise, a fluorided solid oxide and/or asulfated solid oxide, non-limiting examples of which can includefluorided alumina, sulfated alumina, fluorided silica-alumina, sulfatedsilica-alumina, fluorided silica-zirconia, fluorided silica-coatedalumina, fluorided-chlorided silica-coated alumina, or sulfatedsilica-coated alumina, as well as combinations thereof. In yet anotheraspect, the chemically-modified solid oxide can comprise fluoridedalumina; alternatively, chlorided alumina; alternatively, sulfatedalumina; alternatively, fluorided silica-alumina; alternatively,sulfated silica-alumina; alternatively, fluorided silica-zirconia;alternatively, chlorided silica-zirconia; alternatively, sulfatedsilica-coated alumina; alternatively, fluorided-chlorided silica-coatedalumina; or alternatively, fluorided silica-coated alumina. In someaspect, the chemically-modified solid oxide can comprise a fluoridedsolid oxide, while in other aspects, the chemically-modified solid oxidecan comprise a sulfated solid oxide.

Various processes can be used to form chemically-modified solid oxidesuseful in the present invention. Methods of contacting the solid oxidewith the electron-withdrawing component, suitable electron withdrawingcomponents and addition amounts, impregnation with metals or metal ions(e.g., zinc, nickel, vanadium, titanium, silver, copper, gallium, tin,tungsten, molybdenum, zirconium, or combinations thereof), variouscalcining procedures and conditions (e.g., calcining temperatures in arange from 150° C. to 1000° C., from 200° C. to 750° C., or from 400° C.to 700° C.), calcination times (e.g., calcination times in a range from1 minute to 24 hours, from 5 minutes to 10 hours, or from 20 minutes to6 hours), calcination equipment (e.g., calcination equipment such as arotary kiln, muffle furnace, or fluidized bed, among other methods ofconveying heat), and calcination atmospheres (e.g., dry or humidcalcination atmospheres, oxidizing calcination atmospheres such as airor oxygen, reducing calcination atmospheres such as carbon monoxide orhydrogen, or non-reactive calcination atmospheres like nitrogen orargon) are disclosed in, for example, U.S. Pat. Nos. 6,107,230,6,165,929, 6,294,494, 6,300,271, 6,316,553, 6,355,594, 6,376,415,6,388,017, 6,391,816, 6,395,666, 6,524,987, 6,548,441, 6,548,442,6,576,583, 6,613,712, 6,632,894, 6,667,274, 6,750,302, 7,294,599,7,601,665, 7,884,163, and 8,309,485, which are incorporated herein byreference in their entirety. Other suitable processes and procedures forpreparing chemically-modified solid oxides (e.g., sulfated alumina,fluorided silica-alumina, and fluorided silica-coated alumina, amongothers) are well known to those of skill in the art.

Diluents

The processes disclosed herein typically are conducted in the presenceof a diluent. Mixtures and/or combinations of diluents can be utilizedin these processes. The diluent can comprise, consist essentially of, orconsist of, any suitable solvent or any solvent disclosed herein, unlessotherwise specified. For instance, in accordance with one aspect of thisinvention, the diluent can comprise a non-protic solvent. Representativeand non-limiting examples of non-protic solvents can includetetrahydrofuran (THF), 2,5-Me₂THF, acetone, toluene, chlorobenzene,pyridine, carbon dioxide, and the like, as well as combinations thereof.In accordance with another aspect, the diluent can comprise a weaklycoordinating or non-coordinating solvent. Representative andnon-limiting examples of weakly coordinating or non-coordinatingsolvents can include toluene, chlorobenzene, paraffins, halogenatedparaffins, and the like, as well as combinations thereof. In accordancewith yet another aspect, the diluent can comprise a carbonyl-containingsolvent, for instance, ketones, esters, amides, and the like, as well ascombinations thereof. Representative and non-limiting examples ofcarbonyl-containing solvents can include acetone, ethyl methyl ketone,ethyl acetate, propyl acetate, butyl acetate, isobutyl isobutyrate,methyl lactate, ethyl lactate, N,N-dimethylformamide, and the like, aswell as combinations thereof. In still another aspect, the diluent cancomprise THF, 2,5-Me₂THF, methanol, acetone, toluene, chlorobenzene,pyridine, or a combination thereof; alternatively, THF; alternatively,2,5-Me₂THF; alternatively, methanol; alternatively, acetone;alternatively, toluene; alternatively, chlorobenzene; or alternatively,pyridine.

In an aspect, the diluent can comprise (or consist essentially of, orconsist of) an aromatic hydrocarbon solvent. Non-limiting examples ofsuitable aromatic hydrocarbon solvents that can be utilized singly or inany combination include benzene, toluene, xylene (inclusive ofortho-xylene, meta-xylene, para-xylene, or mixtures thereof), andethylbenzene, or combinations thereof; alternatively, benzene;alternatively, toluene; alternatively, xylene; or alternatively,ethylbenzene.

In an aspect, the diluent can comprise (or consist essentially of, orconsist of) a halogenated aromatic hydrocarbon solvent. Non-limitingexamples of suitable halogenated aromatic hydrocarbon solvents that canbe utilized singly or in any combination include chlorobenzene,dichlorobenzene, and combinations thereof alternatively, chlorobenzene;or alternatively, dichlorobenzene.

In an aspect, the diluent can comprise (or consist essentially of, orconsist of) an ether solvent. Non-limiting examples of suitable ethersolvents that can be utilized singly or in any combination includedimethyl ether, diethyl ether, diisopropyl ether, di-n-propyl ether,di-n-butyl ether, diphenyl ether, methyl ethyl ether, methyl t-butylether, dihydrofuran, tetrahydrofuran (THF), 2,5-Me₂THF,1,2-dimethoxyethane, 1,4-dioxane, and combinations thereof;alternatively, diethyl ether, dibutyl ether, THF, 2,5-Me₂THF,1,2-dimethoxyethane, 1,4-dioxane, and combinations thereof;alternatively, THF; or alternatively, diethyl ether.

Metallalactones and Transition Metal-Ligand Complexes

Generally, the processes disclosed herein employ a metallalactone or atransition metal-ligand complex. The transition metal of themetallalactone, or of the transition metal-ligand complex, can be aGroup 3 to Group 8 transition metal or, alternatively, a Group 8 toGroup 11 transition metal. In one aspect, for instance, the transitionmetal can be Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, or Au, while inanother aspect, the transition metal can be Fe, Ni, or Rh.Alternatively, the transition metal can be Fe; alternatively, thetransition metal can be Co; alternatively, the transition metal can beNi; alternatively, the transition metal can be Cu; alternatively, thetransition metal can be Ru; alternatively, the transition metal can beRh; alternatively, the transition metal can be Pd; alternatively, thetransition metal can be Ag; alternatively, the transition metal can beIr; alternatively, the transition metal can be Pt; or alternatively, thetransition metal can Au.

In particular aspects contemplated herein, the transition metal can beNi. Hence, the metallalactone can be a nickelalactone and the transitionmetal-ligand complex can be a Ni-ligand complex in these aspects.

The ligand of the metallalactone, or of the transition metal-ligandcomplex, can be any suitable neutral electron donor group and/or Lewisbase. For instance, the suitable neutral ligands can include sigma-donorsolvents that contain a coordinating atom (or atoms) that can coordinateto the transition metal of the metallalactone (or of the transitionmetal-ligand complex). Examples of suitable coordinating atoms in theligands can include, but are not limited to, O, N, S, and P, orcombinations of these atoms. In some aspects consistent with thisinvention, the ligand can be a bidentate ligand.

In an aspect, the ligand used to form the metallalactone or thetransition metal-ligand complex can be an ether, an organic carbonyl, athioether, an amine, a nitrile, or a phosphine. In another aspect, theligand used to form the metallalactone or the transition metal-ligandcomplex can be an acyclic ether, a cyclic ether, an acyclic organiccarbonyl, a cyclic organic carbonyl, an acyclic thioether, a cyclicthioether, a nitrile, an acyclic amine, a cyclic amine, an acyclicphosphine, or a cyclic phosphine.

Suitable ethers can include, but are not limited to, dimethyl ether,diethyl ether, dipropyl ether, dibutyl ether, methyl ethyl ether, methylpropyl ether, methyl butyl ether, diphenyl ether, ditolyl ether,tetrahydrofuran, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran,2,3-dihydrofuran, 2,5-dihydrofuran, furan, benzofuran, isobenzofuran,dibenzofuran, tetrahydropyran, 3,4-dihydro-2H-pyran,3,6-dihydro-2H-pyran, 2H-pyran, 4H-pyran, 1,3-dioxane, 1,4-dioxane,morpholine, and the like, including substituted derivatives thereof.

Suitable organic carbonyls can include ketones, aldehydes, esters, andamides, either alone or in combination, and illustrative examples caninclude, but are not limited to, acetone, acetophonone, benzophenone,N,N-dimethylformamide, N,N-dimethylacetamide, methyl acetate, ethylacetate, and the like, including substituted derivatives thereof.

Suitable thioethers can include, but are not limited to, dimethylthioether, diethyl thioether, dipropyl thioether, dibutyl thioether,methyl ethyl thioether, methyl propyl thioether, methyl butyl thioether,diphenyl thioether, ditolyl thioether, thiophene, benzothiophene,tetrahydrothiophene, thiane, and the like, including substitutedderivatives thereof.

Suitable nitriles can include, but are not limited to, acetonitrile,propionitrile, butyronitrile, benzonitrile, 4-methylbenzonitrile, andthe like, including substituted derivatives thereof.

Suitable amines can include, but are not limited to, methyl amine, ethylamine, propyl amine, butyl amine, dimethyl amine, diethyl amine,dipropyl amine, dibutyl amine, trimethyl amine, triethyl amine,tripropyl amine, tributyl amine, aniline, diphenylamine, triphenylamine,tolylamine, xylylamine, ditolylamine, pyridine, quinoline, pyrrole,indole, 2-methylpyridine, 3-methylpyridine, 4-methylpyridine,2,5-dimethylpyrrole, 2,5-diethylpyrrole, 2,5-dipropylpyrrole,2,5-dibutylpyrrole, 2,4-dimethylpyrrole, 2,4-diethylpyrrole,2,4-dipropylpyrrole, 2,4-dibutylpyrrole, 3,4-dimethylpyrrole,3,4-diethylpyrrole, 3,4-dipropylpyrrole, 3,4-dibutylpyrrole,2-methylpyrrole, 2-ethylpyrrole, 2-propylpyrrole, 2-butylpyrrole,3-methylpyrrole, 3-ethylpyrrole, 3-propylpyrrole, 3-butylpyrrole,3-ethyl-2,4-dimethylpyrrole, 2,3,4,5 -tetramethylpyrrole,2,3,4,5-tetraethylpyrrole, 2,2′-bipyridine,1,8-diazabicyclo[5.4.0]undec-7-ene, di(2-pyridyl)dimethylsilane,N,N,N′,N′-tetramethylethylenediamine, 1,10-phenanthroline,2,9-dimethyl-1,10-phenanthroline, glyoxal-bis(mesityl)-1,2-diimine andthe like, including substituted derivatives thereof. Suitable amines canbe primary amines, secondary amines, or tertiary amines.

Suitable phosphines and other phosphorus compounds can include, but arenot limited to, trimethylphosphine, triethylphosphine,tripropylphosphine, tributylphosphine, phenylphosphine, tolylphosphine,diphenylphosphine, ditolylphosphine, triphenylphosphine,tritolylphosphine, methyldiphenylphosphine, dimethylphenylphosphine,ethyldiphenylphosphine, diethylphenylphosphine, tricyclohexylphosphine,trimethyl phosphite, triethyl phosphite, tripropyl phosphite,triisopropyl phosphite, tributyl phosphite and tricyclohexyl phosphite,2-(di-t-butylphosphino)biphenyl, 2-di-t-butylphosphino-1,1′-binaphthyl,2-(di-t-butylphosphino)-3,6-dimethoxy-2′,4′,6′-tri-i-propyl-1,1′-biphenyl,2-di-t-butylphosphino-2′-methylbiphenyl,2-(di-t-butylphosphinomethyl)pyridine,2-di-t-butylphosphino-2′,4′,6′-tri-i-propyl-1,1′-biphenyl,2-(dicyclohexylphosphino)biphenyl,(S)-(+)-(3,5-dioxa-4-phospha-cyclohepta[2,1-a;3,4-a′]dinaphthalen-4-yl)dimethylamine,2-(diphenylphosphino)-2′-methoxy-1,1′-binaphthyl,1,2,3,4,5-pentaphenyl-1′-(di-t-butylphosphino)ferrocene,2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (BINAP),1,2-bis(dimethylphosphino)ethane, 1,2-bis(diethylphosphino)ethane,1,2-bi s(dipropylphosphino)-ethane, 1,2-bis(diisopropylphosphino)ethane,1,2-bis(dibutyl-phosphino)ethane, 1,2-bis(di-t-butyl-phosphino)ethane,1,2-bis(dicyclohexylphosphino)ethane,1,3-bis(dicyclohexylphosphino)propane,1,3-bis(diisopropylphosphino)propane, 1,3-bis(diphenylphosphino)propane,1,3 -bis(di-t-butylphosphino)propane,1,4-bis(diisopropylphosphino)butane, 1,4-bis(diphenylphosphino)butane,2,2′-bis[bis(3,5-dimethylphenyl)phosphino]-4,4′,6,6′-tetramethoxybiphenyl,2,6-bis(di-t-butylphosphinomethyl)pyridine,2,2′-bis(dicyclohexylphosphino)-1,1′-biphenyl,bis(2-dicyclohexylphosphinophenyl)ether,5,5′-bis(diphenylphosphino)-4,4′-bi -1,3-benzodioxole,2-t-butylphosphinomethylpyridine, bis(diphenylphosphino)ferrocene,bis(diphenylphosphino)methane, bis(dicyclohexylphosphino)methane,bis(di-t-butylphosphino)methane, and the like, including substitutedderivatives thereof.

In other aspects, the ligand used to form the metallalactone or thetransition metal-ligand complex can be a carbene, for example, aN-heterocyclic carbene (NHC) compound. Representative and non-limitingexamples of suitable N-heterocyclic carbene (NHC) materials include thefollowing:

Illustrative and non-limiting examples of metallalactone complexes(representative nickelalactones) suitable for use as described hereininclude the following compounds (Cy=cyclohexyl, ^(t)Bu=tert-butyl):

The transition metal-ligand complexes corresponding to theseillustrative metallalactones are shown below:

Metallalactones can be synthesized according to the following generalreaction scheme (illustrated with nickel as the transition metal;Ni(COD)₂ is bis(1,5-cyclooctadiene)nickel(0)):

and according to suitable procedures well known to those of skill in theart.

Suitable ligands, transition metal-ligand complexes, and metallalactonesare not limited solely to those ligands, transition metal-ligandcomplexes, and metallalactones disclosed herein. Other suitable ligands,transition metal-ligand complexes, and/or metallalactones are described,for example, in U.S. Pat. Nos. 7,250,510, 8,642,803, and 8,697,909; WO2015/173276; WO 2015/173277; Journal of Organometallic Chemistry, 1983,251, C51-053; Z. Anorg. Allg. Chem., 1989, 577, 111-114; Journal ofOrganometallic Chemistry, 2004, 689, 2952-2962; Organometallics, 2004,Vol. 23, 5252-5259; Chem. Commun., 2006, 2510-2512; Organometallics,2010, Vol. 29, 2199-2202; Chem. Eur. J., 2012, 18, 14017-14025;Organometallics, 2013, 32 (7), 2152-2159; and Chem. Eur. J., 2014, Vol.20, 11, 3205-3211; the disclosures of which are incorporated herein byreference in their entirety.

Producing α,β-Unsaturated Carboxylic Acids and Salts Thereof

Generally, the features of the processes disclosed herein (e.g., themetallalactone, the diluent, the solid promoter (e.g., the treated solidoxide), the α,β-unsaturated carboxylic acid or salt thereof, thetransition metal-ligand complex, the olefin, and the conditions underwhich the α,β-unsaturated carboxylic acid, or a salt thereof, is formed,among others) are independently described, and these features may becombined in any combination to further describe the disclosed processes.

In accordance with an aspect of the present invention, a process forperforming a metallalactone elimination reaction is disclosed. Thisprocess can comprise (or consist essentially of, or consist of):

(1) contacting

-   -   (a) a metallalactone;    -   (b) a diluent; and    -   (c) a solid promoter (e.g., a treated solid oxide); and

(2) forming an α,β-unsaturated carboxylic acid, or a salt thereof.

Suitable metallalactones, diluents, and solid promoters (e.g., treatedsolid oxides) are disclosed hereinabove. In this process for performinga metallalactone elimination reaction, for instance, at least a portionof the diluent can comprise the α,β-unsaturated carboxylic acid, or thesalt thereof, that is formed in step (2) of this process.

In accordance with another aspect of the present invention, a processfor producing an α,β-unsaturated carboxylic acid, or a salt thereof, isdisclosed. This process can comprise (or consist essentially of, orconsist of):

(1) contacting

-   -   (a) a metallalactone;    -   (b) a diluent; and    -   (c) a solid promoter (e.g., a treated solid oxide);

(2) forming an adduct of an α,β-unsaturated carboxylic acid adsorbedonto the solid promoter; and

(3) treating the adduct adsorbed onto the solid promoter to produce theα,β-unsaturated carboxylic acid, or the salt thereof.

In this process for producing an α,β-unsaturated carboxylic acid or asalt thereof, for instance, at least a portion of the diluent comprisinga transition metal of the metallalactone can be removed after step (2),and before step (3), of this process. Suitable metallalactones,diluents, and solid promoters (e.g., treated solid oxides) are disclosedhereinabove.

In some aspects, the contacting step—step (1)—of these processes caninclude contacting, in any order, the metallalactone, the diluent, andthe solid promoter (e.g., the treated solid oxide), and additionalunrecited materials. In other aspects, the contacting step can consistessentially of, or consist of, the metallalactone, the diluent, and thesolid promoter (e.g., the treated solid oxide) components. Likewise,additional materials or features can be employed in the formingstep—step (2)—of these processes, and/or in the treating step—step(3)—of the process for producing the α,β-unsaturated carboxylic acid, orthe salt thereof. Further, it is contemplated that these processes forperforming a metallalactone elimination reaction and for producing anα,β-unsaturated carboxylic acid, or a salt thereof, can employ more thanone metallalactone and/or more than one solid promoter (e.g., a mixtureof two treated solid oxides). Additionally, a mixture or combination oftwo or more diluents can be employed, if desired.

Any suitable reactor, vessel, or container can be used to contact themetallalactone, diluent, and solid promoter (e.g., treated solid oxide),non-limiting examples of which can include a flow reactor, a continuousreactor, a fixed bed reactor, and a stirred tank reactor, including morethan one reactor in series or in parallel, and including any combinationof reactor types and arrangements. In particular aspects consistent withthis invention, the metallalactone and the diluent contact a fixed bedof the solid promoter (e.g., the treated solid oxide), for instance, ina suitable vessel, such as in a continuous fixed bed reactor. In furtheraspects, combinations of more than one solid promoter can be used, suchas a mixed bed of a first treated solid oxide and a second treated solidoxide, or sequential beds of a first treated solid oxide and a secondtreated solid oxide. In these and other aspects, the feed stream canflow upward or downward through the fixed bed. For instance, themetallalactone and the diluent can contact the first treated solid oxideand then the second treated solid oxide in a downward flow orientation,and the reverse in an upward flow orientation. In a different aspect,the metallalactone and the solid promoter (e.g., the treated solidoxide) can be contacted by mixing or stirring in the diluent, forinstance, in a suitable vessel, such as a stirred tank reactor.

Step (2) of the process for producing an α,β-unsaturated carboxylicacid, or a salt thereof, recites forming an adduct of theα,β-unsaturated carboxylic acid adsorbed onto the solid promoter (e.g.,the treated solid oxide). This adduct can contain all or a portion ofthe α,β-unsaturated carboxylic acid, and is inclusive of salts of theα,β-unsaturated carboxylic acid.

In step (3) of the process for producing an α,β-unsaturated carboxylicacid or a salt thereof, the adduct adsorbed onto the solid promoter(e.g., the treated solid oxide) is treated to produce theα,β-unsaturated carboxylic acid, or the salt thereof. Various methodscan be used to liberate or desorb the α,β-unsaturated carboxylic acid,or the salt thereof, from the solid promoter (e.g., the treated solidoxide). In one aspect, for instance, the treating step can comprisecontacting the adduct adsorbed onto the solid promoter (e.g., thetreated solid oxide) with an acid. Representative and non-limitingexamples of suitable acids can include HCl, acetic acid, sodiumbisulfate, and the like, as well as combinations thereof. In anotheraspect, the treating step can comprise contacting the adduct adsorbedonto the solid promoter (e.g., the treated solid oxide) with a base.Representative and non-limiting examples of suitable bases can includecarbonates (e.g., Na₂CO₃, Cs₂CO₃, MgCO₃), hydroxides (e.g., Mg(OH)₂,Na(OH), alkoxides (e.g., Al(O^(i)Pr)₃, Na(O^(t)Bu), Mg(OEt)₂), and thelike, as well as combinations thereof (^(i)Pr=isopropyl,^(t)Bu=tert-butyl, Et=ethyl). In yet another aspect, the treating stepcan comprise contacting the adduct adsorbed onto the solid promoter(e.g., the treated solid oxide) with a suitable solvent. Representativeand non-limiting examples of suitable solvents can includecarbonyl-containing solvents such as ketones, esters, or amides (e.g.,acetone, ethyl acetate, or N,N-dimethylformamide, as described hereinabove), alcohol solvents, water, and the like, as well as combinationsthereof. In still another aspect, the treating step can comprise heatingthe adduct adsorbed onto the solid promoter (e.g., the treated solidoxide) to any suitable temperature. This temperature can be in a range,for example, from 50° C. to 1000° C., from 100° C. to 800° C., from 150°C. to 600° C., from 250° C. to 1000° C., from 250° C. to 550° C., orfrom 150° C. to 500° C. The duration of this heating step is not limitedto any particular period of time, as long of the period of time issufficient to liberate the α,β-unsaturated carboxylic acid from thesolid promoter (e.g., the treated solid oxide). As those of skill in theart recognize, the appropriate treating step depends upon severalfactors, such as the particular diluent used in the process, and theparticular solid promoter (e.g., treated solid oxide) used in theprocess, amongst other considerations.

In these processes for performing a metallalactone elimination reactionand for producing an α,β-unsaturated carboxylic acid (or a saltthereof), additional process steps can be conducted before, during,and/or after any of the steps described herein. As an example, theseprocesses can further comprise a step (e.g., prior to step (1)) ofcontacting a transition metal-ligand complex with an olefin and carbondioxide (CO₂) to form the metallalactone. Transition metal-ligandcomplexes are described hereinabove. Illustrative and non-limitingexamples of suitable olefins can include ethylene, propylene, butene(e.g., 1-butene), pentene, hexene (e.g., 1-hexene), heptene, octene(e.g., 1-octene), styrene, and the like, as well as combinationsthereof.

Yet, in accordance with another aspect of the present invention, aprocess for producing an α,β-unsaturated carboxylic acid, or a saltthereof, is disclosed. This process can comprise (or consist essentiallyof, or consist of):

(I) contacting

-   -   (i) a transition metal-ligand complex;    -   (ii) an olefin;    -   (iii) carbon dioxide (CO₂);    -   (iv) a diluent; and    -   (v) a solid promoter (e.g., a treated solid oxide); and

(II) forming the α,β-unsaturated carboxylic acid, or the salt thereof.

Suitable transition metal-ligands, olefins, diluents, and solidpromoters (e.g., treated solid oxides) are disclosed hereinabove. Insome aspects, the contacting step—step (I)—of this process can includecontacting, in any order, the transition metal-ligand, the olefin, thediluent, the solid promoter (e.g., the treated solid oxide), and carbondioxide, and additional unrecited materials. In other aspects, thecontacting step can consist essentially of, or consist of, contacting,in any order, the transition metal-ligand, the olefin, the diluent, thesolid promoter (e.g., the treated solid oxide), and carbon dioxide.Likewise, additional materials or features can be employed in theforming step—step (II)—of this process. Further, it is contemplated thatthis process for producing an α,β-unsaturated carboxylic acid, or a saltthereof, can employ more than one transition metal-ligand complex,and/or more than one solid promoter (e.g., a mixture of two treatedsolid oxides), and/or more than one olefin. Additionally, a mixture orcombination of two or more diluents can be employed. As above, anysuitable reactor, vessel, or container can be used to contact thetransition metal-ligand, olefin, diluent, solid promoter (e.g., treatedsolid oxide), and carbon dioxide, whether using a fixed bed of the solidpromoter (e.g., the treated solid oxide), a stirred tank for contacting(or mixing), or some other reactor configuration and process. While notwishing to be bound by the following theory, a proposed and illustrativereaction scheme for this process is provided below (R is H, Na, or K,although not limited thereto):

Independently, the contacting and forming steps of any of the processesdisclosed herein (i.e., for performing a metallalactone eliminationreaction, for producing an α,β-unsaturated carboxylic acid, or a saltthereof), can be conducted at a variety of temperatures, pressures, andtime periods. For instance, the temperature at which the components instep (1) or step (I) are initially contacted can be the same as, ordifferent from, the temperature at which the forming step is performed.As an illustrative example, in the contacting step, the components canbe contacted initially at temperature T1 and, after this initialcombining, the temperature can be increased to a temperature T2 for theforming step (e.g., to form the α,β-unsaturated carboxylic acid, or thesalt thereof). Likewise, the pressure can be different in the contactingstep and the forming step. Often, the time period in the contacting stepcan be referred to as the contact time, while the time period in formingstep can be referred to as the reaction time. The contact time and thereaction time can be, and often are, different.

In an aspect, the contacting step and/or the forming step of theprocesses disclosed herein can be conducted at a temperature in a rangefrom 0° C. to 250° C.; alternatively, from 20° C. to 200° C.;alternatively, from 0° C. to 95° C.; alternatively, from 10° C. to 75°C.; alternatively, from 10° C. to 50° C.; or alternatively, from 15° C.to 70° C. In these and other aspects, after the initial contacting, thetemperature can be changed, if desired, to another temperature for theforming step. These temperature ranges also are meant to encompasscircumstances where the contacting step and/or the forming step can beconducted at a series of different temperatures, instead of at a singlefixed temperature, falling within the respective ranges.

In an aspect, the contacting step and/or the forming step of theprocesses disclosed herein can be conducted at a pressure in a rangefrom 5 to 10,000 psig, such as, for example, from 5 to 2500 psig. Insome aspects, the pressure can be in a range from 5 to 500 psig;alternatively, from 25 to 3000 psig; alternatively, from 45 to 1000psig; or alternatively, from 50 to 250 psig.

The contacting step of the processes is not limited to any particularduration of time. That is, the respective components can be initiallycontacted rapidly, or over a longer period of time, before commencingthe forming step. Hence, the contacting step can be conducted, forexample, in a time period ranging from as little as 1-30 seconds to aslong as 1-12 hours, or more. In non-continuous or batch operations, theappropriate reaction time for the forming step can depend upon, forexample, the reaction temperature, the reaction pressure, and the ratiosof the respective components in the contacting step, among othervariables. Generally, however, the forming step can occur over a timeperiod that can be in a range from 1 minute to 96 hours, such as, forexample, from 2 minutes to 96 hours, from 5 minutes to 72 hours, from 10minutes to 72 hours, or from 15 minutes to 48 hours.

If the process employed is a continuous process, then themetallalactone/solid promoter catalyst contact/reaction time (or thetransition metal-ligand/solid promoter catalyst contact/reaction time)can be expressed in terms of weight hourly space velocity (WHSV)—theratio of the weight of the metallalactone (or transition metal-ligandcomplex) which comes in contact with a given weight of solid promoter(e.g., treated solid oxide) per unit time. While not limited thereto,the WHSV employed, based on the amount of the solid promoter (e.g., thetreated solid oxide), can be in a range from 0.05 to 100, from 0.05 to50, from 0.075 to 50, from 0.1 to 25, from 0.5 to 10, from 1 to 25, orfrom 1 to 5.

In the processes disclosed herein, the molar yield of theα,β-unsaturated carboxylic acid, or the salt thereof), based on themetallalactone (or based on the transition metal of the transitionmetal-ligand complex) is at least 2%, and more often can be at least 5%,at least 10%, or at least 15%. In particular aspects of this invention,the molar yield can be at least 25%, at least 50%, at least 75%, atleast 100%, at least 125%, at least 150%, at least 200%, or at least350%, and often can range up to 10,000%, or 100,000%, or 1,000,000%, ascatalytic efficiencies are realized.

The specific α,β-unsaturated carboxylic acid (or salt thereof) that canbe formed or produced using the processes of this invention is notparticularly limited. Illustrative and non-limiting examples of theα,β-unsaturated carboxylic acid can include acrylic acid, methacrylicacid, 2-ethylacrylic acid, cinnamic acid and the like, as well ascombinations thereof. Illustrative and non-limiting examples of the saltof the α,β-unsaturated carboxylic acid can include sodium acrylate,magnesium acrylate, sodium methacrylate, and the like, as well ascombinations thereof.

Once formed, the α,β-unsaturated carboxylic acid (or salt thereof) canbe purified and/or isolated and/or separated using suitable techniqueswhich can include, but are not limited to, evaporation, distillation,chromatography, crystallization, extraction, washing, decanting,filtering, drying, and the like, including combinations of more than oneof these techniques. In an aspect, the process for performing ametallalactone elimination reaction (or the process for producing anα,β-unsaturated carboxylic acid, or a salt thereof) can further comprisea step of separating or isolating the α,β-unsaturated carboxylic acid(or salt thereof) from other components, such as the diluent and/or thesolid promoter (e.g., the treated solid oxide). For instance, asolid-liquid separations technique can be used.

EXAMPLES

The invention is further illustrated by the following examples, whichare not to be construed in any way as imposing limitations to the scopeof this invention. Various other aspects, modifications, and equivalentsthereof which, after reading the description herein, may suggestthemselves to one of ordinary skill in the art without departing fromthe spirit of the present invention or the scope of the appended claims.

The following nickelalactone complexes, which can be derived fromCO₂-ethylene coupling, were used to evaluate various homogeneous andheterogeneous (solid) promoters in certain examples that follow.

The general nickelalactone elimination reaction was performed asfollows. A flask was charged with 10 mg of nickelalactone (A, B, or C),promoter, and approximately 10 mL of diluent. The reaction mixture washeated with vigorous stirring on an oil bath under conditions describedin the examples below. The reaction mixture was allowed to cool toambient temperature, then acidified. The yield of acrylic acid wasdetermined by ¹H NMR in D₆-acetone versus an internal standard sorbicacid stock solution.

Examples 1-8 Evaluation of Homogeneous Activators/Promoters—AcrylateElimination

For Examples 1-8, 5 equivalents of the activator/promoter (per Ni) wereincubated with the nickelalactone (A, B, or C) at 50° C. for 3 hours,followed by eventual acid hydrolysis and extraction to quantify theamount of acrylic acid by ¹H NMR against an internal standard, asreflected in the following reaction scheme:

The results of the evaluation of the homogeneous activators/promotersare summarized in Table I. The diluents employed in Example 1 andExamples 2-7 were 5:1 tetrahydrofuran/acetone and tetrahydrofuran,respectively. Example 8 was investigated in tetrahydrofuran, methanol,and acetone. The homogeneous promoter of Example 5 was a solution ofmethylaluminoxane in toluene, while the homogeneous promoter of Example6 was a mixture of Mg(^(n)Bu)₂ and methanol, which results in analkoxide. As shown in Table I, the homogeneous activators/promoters ofExamples 1-8 failed to yield any acrylic acid with any of thenickelalactones investigated.

TABLE I Molar Yields of Examples 1-8. Example Promoter A B C 1 Na₂(CO₃)0 0 0 2 Al(CH₂CH₃)₃ 0 0 0 3 Al(OCH₂CH₃)₃ 0 0 0 4 Ti(O^(i)Pr)₄ 0 — — 5(Al(CH₃)O)_(n) 0 — — 6 Mg(^(n)Bu)₂ + MeOH 0 — — 7 Ca(OMe)₂ 0 — — 8Mg(OH)₂ 0 — — Notes: Me = methyl; ^(i)Pr = isopropyl; ^(n)Bu = n-butyl.

Examples 9-12 Evaluation of Solid/HeterogeneousActivators/Promoters—Acrylate Elimination

Examples 9-12 were performed in a manner similar to that of Examples2-7, as reflected in the following reaction scheme (25 equivalents perNi were based on site concentration (mmol/g) of the solidactivator/promoter; HCl was used to liberate the acrylic acid foranalysis):

The results of the evaluation of the solid/heterogeneousactivators/promoters (calcined at 400° C.) are summarized in Table II.Unexpectedly, in contrast with the homogeneous Al and Mg promoters ofExamples 2-3, 5-6, and 8, the solid promoters of Examples 9-12 produceda measurable amount of acrylic acid. More surprisingly, Example 11A and11C (zirconia) and Example 12A and 12C (magnesia) provided significantmolar yields of acrylic acid (from 20% to 90%).

TABLE II Molar Yields of Examples 9-12. Site conc. Example Promoter(mmol/g) A B C 9 alumina 5.4  0 0 11 10 silica-magnesia 5.3 Trace 0 0 11zirconia 1.3 23 0 23 12 magnesia 1.1 88 6 58

Examples 13-24 Evaluation of Solid/HeterogeneousActivators/Promoters—Acrylate Elimination

Examples 13-24 were performed in a manner similar to that of Examples9-12, with only nickelalactone A, as reflected in the following reactionscheme (25 equivalents per Ni were based on site concentration (mmol/g)of the solid activator/promoter; HCl was used to liberate the acrylicacid for analysis):

The results of the evaluation of the solid/heterogeneousactivators/promoters (calcined at 400° C.) in differentdiluents/solvents are summarized in Table III. Unexpectedly, alumina,zirconia, magnesia, magnesium aluminate, and sepiolite producedsignificant amounts of acrylic acid using different diluents, withgenerally from 5% to 90% molar yield.

Magnesium aluminate was further tested under different calciningconditions. At 400° C. in THF diluent, the yield was 37%. Calcining at250° C. reduced the yield to 6%, while calcining at 550° C. increasedthe yield to 47%.

Examples 25-33 Evaluation of Treated Solid Oxides—Acrylate Elimination

Examples 25-33 were performed by mixing 18 μmol of the nickel compound,18 μmol of the diphosphine ligand, 5 mL of diluent (THF or toluene), andthe treated solid oxide (200 mg for Examples 25-30, 50 mg for Examples31-33) at 60° C. for 30 to 60 minutes, as reflected in the followingreaction scheme:

Aqueous sodium bisulfate was used to liberate the acrylic acid foranalysis, followed by extraction into D₂O/acetone-d₆ to quantify theamount of acrylic acid by ¹H NMR spectroscopy relative to an internalsorbic acid standard.

The alumina used in Example 30, and used as the base material forExamples 25-29, 34-37, 39, and 41, had a pore volume of 1.3 mL/g and asurface area of 330 m²/g. For Example 30, the alumina was calcined at500° C. in dry air for 3 hours.

The zinc-treated alumina of Example 25 was prepared by mixing 10 g ofalumina with 30 mL of an aqueous solution containing 2.5 g of zincchloride. After removing the water in a vacuum oven at 90° C. overnight,the dried powder was calcined at 500° C. in dry air for three hours. Thecalcium-treated aluminas of Examples 27 and 29 were prepared similarly,except that calcining was performed at 600° C. in dry air for 3 hours.

The chlorided alumina of Example 26 was prepared by injecting 3 mL ofCCl₄ liquid (and vaporizing the CCl₄) over a period of less than 1minute into a nitrogen gas stream used to calcine the alumina at 500° C.for three hours, resulting in chlorided alumina.

The sodium-treated alumina of Example 28 was prepared by mixing 22.8 gof alumina with 60 mL of an aqueous solution containing 4.6 g of sodiumbicarbonate. After removing the water in a vacuum oven at 90° C.overnight, the dried powder was calcined at 200° C. in dry air for threehours.

In Example 31 and Example 32, sodium bicarbonate and cesium carbonate,respectively, were calcined at 200° C. in dry air for 6 hours, while inExample 33, sodium carbonate was not calcined (untreated).

The results of the evaluation of the treated solid oxides and untreatedsodium carbonate of Examples 25-33 are summarized in Table IV.Unexpectedly, in contrast with the chlorided alumina of Example 26, thetreated solid oxides of Examples 25 and 27-30 produced significantamounts of acrylic acid, with molar yields ranging from approximately 3%to 27%. Also unexpectedly, the calcined carbonates of Examples 31-32yielded acrylic acid, while the uncalcined Example 33 did not.

Examples 34-41 Evaluation of Treated Solid Oxides—Direct Conversion ofCO₂ and Ethylene to Acrylate

Examples 34-41 were performed by mixing 0.1 mmol of the nickel compound,0.11 mmol of the diphosphine ligand, 500 mL of the diluent, and 1 g ofthe treated solid oxide in a reactor equilibrated with 150 psigethylene, followed by 300 psig carbon dioxide, and then heating to 100°C. for 6 hours, as reflected in the following reaction scheme:

The reaction product was extracted into D₂O/acetone-d₆ for acrylateyield determination by ¹H NMR spectroscopy relative to an internalsorbic acid standard.

The sodium-treated sulfated alumina of Example 34 was prepared by mixingalumina with a solution of sulfuric acid in methanol, to result inapproximately 15 wt. % sulfate based on the weight of the sulfatedalumina. After drying under vacuum at 110° C. overnight, the driedpowder was calcined at 600° C. in dry air for three hours. Aftercooling, 4.2 g of the sulfated alumina and 2 g of sodium tert-butoxidewere combined in 60 mL of toluene, forming a yellow suspension. Themixture was stirred at ambient temperature for 18 hours, filtered, andwashed with 10 mL of toluene, forming the colorless solid(sodium-treated sulfated alumina) of Example 34.

The sodium-treated chlorided alumina of Example 36 was prepared usingthe chlorided alumina of Example 26, and following the same sodiumtreatment procedure used in Example 34.

The fluorided silica-coated alumina of Example 41 was prepared by firstcontacting alumina with tetraethylorthosilicate in isopropanol to equal25 wt. % SiO₂. After drying, the silica-coated alumina was calcined at600° C. for 3 hours. Next, the fluorided silica-coated alumina (7 wt. %F) was prepared by impregnating the calcined silica-coated alumina withan ammonium bifluoride solution in methanol, drying, and then calciningat 600° C. for 3 hours. The sodium-treated fluorided silica-coatedalumina of Example 35 was prepared using the fluorided silica-coatedalumina of Example 41, and following the same sodium treatment procedureused in Example 34.

The sodium-treated sulfated silica-coated alumina (8 wt. % sulfate) ofExample 37 was prepared using silica-coated alumina prepared asdescribed in Example 41, and then sulfating and sodium treating in themanner described in Example 34.

The sodium-treated fluorided silica-alumina of Example 38 used asilica-alumina having 13% alumina by weight, a surface area of 400 m²/g,and a pore volume of 1.2 mL/g, as a base material. This material wasmixed with an aqueous solution containing ammonium hydrogen fluoride,dried under vacuum at 110° C. overnight, and calcined at 450° C. in dryair for three hours. The fluorided silica-alumina was then sodiumtreated in the same manner as described in Example 34.

The sodium-treated tungsten alumina of Example 39 was prepared by firstsaturating 12.91 g of alumina (surface area of 300 m², pore volume of1.2 mL/g, average particle size of 100 microns) with an aqueous solutionof 6.341 g of ammonium metatungstate hydrate in 50 mL of deionized waterto give a wet sand consistency. After isolating and drying the solid,the solid was calcined at 600° C. for 3 hours. The sodium treatment wasperformed in the same manner as described in Example 34.

The sodium-treated aluminophosphate of Example 40 was prepared by firstadding 100 mL of deionized water to 1 mole of aluminum nitratenonahydrate, and heating the mixture to 60° C., which resulted in auniform clear liquid. Then, 0.9 mol of ammonium phosphate dibasic wasadded and dissolved into the solution. After 1 hour of stirring at 60°C., concentrated ammonium hydroxide was added until gelation occurred,forming a hard solid. The solid was broken up into smaller pieces, andwashed three times in 4 L of warm deionized water. A final wash wasaccomplished in 4 L of n-propanol, followed by filtration, and thendrying in a vacuum oven at 110° C. The dried powder was then calcined at600° C. for 3 hours, and subsequently sodium treated in the mannerdescribed in Example 34.

The results of the evaluation of the treated solid oxides of Examples34-41 are summarized in Table V. Unexpectedly, in contrast with thefluorided silica-coated alumina of Example 41 (which produced no acrylicacid), the treated solid oxides of Examples 34-40 produced significantamounts of acrylic acid, with from 38% to 181% molar yield. Themetal-treated chemically-modified solid oxides of Examples 34-35 and37-38 were particularly successful in catalytically producing acrylicacid directly from CO₂ and ethylene, with molar yields in excess of 100%(based on the transition metal of the transition metal-ligand complex).

TABLE III Molar Yields of Examples 13-24. Site conc. Example Promoter(mmol/g) THF 2,5-Me₂ THF Methanol Acetone Toluene Chlorobenzene 13Silica 1.0 0 — — 0 0 0 14 Alumina 5.4 10 — 0 12 12 38 15 silica-alumina5.0 4 — — 0 0 0 16 aluminum phosphate 4.0 0 — — 0 0 0 17 alumina-boria5.4 trace — — 0 0 trace 18 silica-magnesia 5.3 trace — 0 trace 0 0 19silica-titania 5.4 6 — — 0 0 0 20 Zirconia 1.3 23 — 0 5 0 — 21 Magnesia1.1 88 27 0 33 18 45 22 magnesium aluminate 1.1 37 30 — — 43 41 23Sepiolite 2.2 17 — — 0 trace 12 24 Titania 1.4 0 — — 0 0 0

TABLE IV Examples 25-33. Calcination Acrylic Acid Temperature MolarYield Example Treated Solid Oxide (° C.) Diluent (%) 25 ZnCl₂-alumina500 THF 2.8 26 CCl₄-alumina 500 THF 1.3 27 Ca(NO₃)₂-alumina 600 THF 13.828 NaHCO₃-alumina 200 Toluene 8.5 29 Ca(NO₃)₂-alumina 600 Toluene 27 30alumina 500 Toluene 7.1 31 NaHCO₃ 200 Toluene 6.2 32 CsCO₃ 200 Toluene2.8 33 Untreated Na₂CO₃ N/A Toluene 0

TABLE V Examples 34-41. Acrylate Exam- Molar Yield ple Treated SolidOxide Diluent (%) 34 NaO^(t)Bu sulfated alumina Toluene 102 35 NaO^(t)Bufluorided silica-coated alumina Toluene 131 36 NaO^(t)Bu chloridedalumina Toluene 38 37 NaO^(t)Bu sulfated silica-coated alumina Toluene181 38 NaO^(t)Bu fluorided silica-alumina Toluene 118 39 NaO^(t)Butungsten alumina Toluene 76 40 NaO^(t)Bu aluminophosphate Toluene 95 41fluorided silica-coated alumina Toluene 0

The invention is described above with reference to numerous aspects andspecific examples. Many variations will suggest themselves to thoseskilled in the art in light of the above detailed description. All suchobvious variations are within the full intended scope of the appendedclaims. Other aspects of the invention can include, but are not limitedto, the following (aspects typically are described as “comprising” but,alternatively, can “consist essentially of” or “consist of” unlessspecifically stated otherwise):

Aspect 1. A process for performing a metallalactone eliminationreaction, the process comprising:

(1) contacting

-   -   (a) a metallalactone;    -   (b) a diluent; and    -   (c) a treated solid oxide; and

(2) forming an α,β-unsaturated carboxylic acid, or a salt thereof.

Aspect 2. The process defined in aspect 1, wherein at least a portion ofthe diluent comprises the α,β-unsaturated carboxylic acid, or the saltthereof, formed in step (2).

Aspect 3. A process for producing an α,β-unsaturated carboxylic acid, ora salt thereof, the process comprising:

(1) contacting

-   -   (a) a metallalactone;    -   (b) a diluent; and    -   (c) a treated solid oxide;

(2) forming an adduct of an α,β-unsaturated carboxylic acid adsorbedonto the treated solid oxide; and

(3) treating the adduct adsorbed onto the treated solid oxide to producethe α,β-unsaturated carboxylic acid, or the salt thereof.

Aspect 4. The process defined in aspect 3, wherein at least a portion ofthe diluent comprising a transition metal of the metallalactone isremoved after step (2).

Aspect 5. The process defined in any one of aspects 1-4, wherein in step(1), the metallalactone and the diluent contact a fixed bed of thetreated solid oxide.

Aspect 6. The process defined in any one of aspects 1-4, wherein in step(1), the metallalactone and the treated solid oxide are contacted bymixing/stirring in the diluent.

Aspect 7. The process defined in any one of aspects 3-6, wherein thetreating step comprises contacting the adduct adsorbed onto the treatedsolid oxide with any suitable acid, or any acid disclosed herein, e.g.,HCl, sodium bisulfate, or acetic acid.

Aspect 8. The process defined in any one of aspects 3-6, wherein thetreating step comprises contacting the adduct adsorbed onto the treatedsolid oxide with any suitable base, or any base disclosed herein, e.g.,carbonates (e.g., Na₂CO₃, Cs₂CO₃, MgCO₃), hydroxides (e.g., Mg(OH)₂,NaOH), or alkoxides (e.g., Al(O^(i)Pr)₃, Na(O^(t)Bu), Mg(OEt)₂).

Aspect 9. The process defined in any one of aspects 3-6, wherein thetreating step comprises contacting the adduct adsorbed onto the treatedsolid oxide with any suitable solvent, or any solvent disclosed herein,e.g., carbonyl-containing solvents such as ketones, esters, or amides(e.g., acetone, ethyl acetate, N,N-dimethylformamide), alcohol solvents,or water.

Aspect 10. The process defined in any one of aspects 3-6, wherein thetreating step comprises heating the adduct adsorbed onto the treatedsolid oxide to any suitable temperature, or a temperature in any rangedisclosed herein, e.g., from 50° C. to 1000° C., from 100° C. to 800°C., from 150° C. to 600° C., or from 250° C. to 550° C.

Aspect 11. The process defined in any one of the preceding aspects,further comprising a step of contacting a transition metal-ligandcomplex with an olefin and carbon dioxide (CO₂) to form themetallalactone.

Aspect 12. A process for producing an α,β-unsaturated carboxylic acid,or a salt thereof, the process comprising:

(I) contacting

-   -   (i) a transition metal-ligand complex;    -   (ii) an olefin;    -   (iii) carbon dioxide (CO₂);    -   (iv) a diluent; and    -   (v) a treated solid oxide; and

(II) forming the α,β-unsaturated carboxylic acid, or the salt thereof.

Aspect 13. The process defined in aspect 11 or 12, wherein the olefincomprises any suitable olefin or any olefin disclosed herein, e.g.,ethylene, propylene, or 1-butene.

Aspect 14. The process defined in any one of aspects 1-13, wherein theα,β-unsaturated carboxylic acid, or a salt thereof, comprises anysuitable α,β-unsaturated carboxylic acid, or any α,β-unsaturatedcarboxylic acid disclosed herein, or a salt thereof, e.g., acrylic acid,methacrylic acid, 2-ethylacrylic acid, cinnamic acid, sodium acrylate,magnesium acrylate, or sodium methacrylate.

Aspect 15. The process defined in any one of aspects 1-14, wherein themolar yield of the α,β-unsaturated carboxylic acid, or the salt thereof,based on the metallalactone (or based on the transition metal of thetransition metal-ligand complex) is in any range disclosed herein, e.g.,at least 5%, at least 10%, at least 15%, at least 25%, at least 50%, atleast 100%, at least 150%, or at least 200%.

Aspect 16. The process defined in any one of aspects 1-15, wherein theprocess further comprises a step of isolating the α,β-unsaturatedcarboxylic acid, or the salt thereof, e.g., using any suitableseparation/purification procedure or any separation/purificationprocedure disclosed herein, e.g., evaporation, distillation, orchromatography.

Aspect 17. The process defined in any one of aspects 1-16, wherein thecontacting step and/or the forming step is/are conducted at any suitablepressure or at any pressure disclosed herein, e.g., from 5 psig to10,000 psig, or from 45 psig to 1000 psig.

Aspect 18. The process defined in any one of aspects 1-17, wherein thecontacting step and/or the forming step is/are conducted at any suitabletemperature or at any temperature disclosed herein, e.g., from 0° C. to250° C., from 0° C. to 95° C., or from 15° C. to 70° C.

Aspect 19. The process defined in any one of aspects 1-18, wherein thecontacting step is conducted at any suitable weight hourly spacevelocity (WHSV) or any WHSV disclosed herein, e.g., from 0.05 to 50,from 1 to 25, or from 1 to 5, based on the amount of the treated solidoxide.

Aspect 20. The process defined in any one of aspects 1-19, wherein thetreated solid oxide is a Lewis acid.

Aspect 21. The process defined in any one of aspects 1-19, wherein thetreated solid oxide is a Brønsted base.

Aspect 22. The process defined in any one of aspects 1-19, wherein thetreated solid oxide is a Brønsted base and a Lewis acid.

Aspect 23. The process defined in any one of aspects 1-22, wherein thetreated solid oxide comprises any suitable solid oxide, or any solidoxide disclosed herein.

Aspect 24. The process defined in aspect 23, wherein the solid oxidecomprises Al₂O₃, B₂O₃, BeO, Bi₂O₃, CdO, Co₃O₄, Cr₂O₃, CuO, Fe₂O₃, Ga₂O₃,La₂O₃, Mn₂O₃, MoO₃, Na₂O, NiO, P₂O₅, Sb₂O₅, SiO₂, SnO₂, SrO, ThO₂, TiO₂,V₂O₅, WO₃, Y₂O₃, ZnO, ZrO₂, K₂O, CaO, La₂O₃, or Ce₂O₃, including mixedoxides thereof, and combinations thereof.

Aspect 25. The process defined in aspect 23, wherein the solid oxidecomprises silica, alumina, titania, zirconia, magnesia, boria, calcia,zinc oxide, silica-alumina, silica-coated alumina, silica-titania,silica-zirconia, silica-magnesia, alumina-titania, alumina-zirconia,zinc-aluminate, alumina-boria, silica-boria, aluminum phosphate,aluminophosphate, aluminophosphate-silica, magnesium aluminate,titania-zirconia, or a combination thereof.

Aspect 26. The process defined in aspect 23, wherein the solid oxidecomprises magnesium aluminate, calcium aluminate, zinc aluminate,zirconium aluminate, sodium aluminate, magnesium zirconium oxide, sodiumzirconium oxide, calcium zirconium oxide, lanthanum chromium oxide,barium titanium oxide, or a combination thereof.

Aspect 27. The process defined in aspect 23, wherein the solid oxidecomprises sodium carbonate, sodium bicarbonate, potassium carbonate,cesium carbonate, or a combination thereof.

Aspect 28. The process defined in any one of aspects 1-27, wherein thetreated solid oxide is a calcined solid oxide.

Aspect 29. The process defined in any one of aspects 1-28, wherein priorto step (1) or step (I), the treated solid oxide is formed by calciningat any suitable temperature, or at a temperature in any range disclosedherein, e.g. from 150° C. to 1000° C., from 200° C. to 750° C., or from200° C. to 600° C.

Aspect 30. The process defined in any one of aspects 1-27, wherein thetreated solid oxide is a metal-treated solid oxide.

Aspect 31. The process defined in aspect 30, wherein prior to step (1)or step (I), the metal-treated solid oxide is produced by a processcomprising contacting any suitable solid oxide and any suitablemetal-containing compound and calcining (concurrently and/orsubsequently).

Aspect 32. The process defined in aspect 30 or 31, wherein themetal-treated solid oxide comprises an alkali metal, an alkaline earthmetal, a transition metal, or any combination thereof, and generally atan amount in a range from 1 to 30 wt. %, from 5 to 25 wt. %, or from 6to 18 wt. %, based on the total weight of the metal-treated solid oxide.

Aspect 33. The process defined in any one of aspects 30-32, wherein themetal-treated solid oxide comprises an alkali metal (an alkalimetal-treated solid oxide), e.g., sodium, potassium, or cesium, as wellas combinations thereof.

Aspect 34. The process defined in any one of aspects 30-32, wherein themetal-treated solid oxide comprises an alkaline earth metal (an alkalineearth metal-treated solid oxide), e.g., magnesium, calcium, or barium,as well as combinations thereof.

Aspect 35. The process defined in any one of aspects 30-32, wherein themetal-treated solid oxide comprises a transition metal (a transitionmetal-treated solid oxide), e.g., titanium, zirconium, hafnium,tungsten, or zinc, as well as combinations thereof.

Aspect 36. The process defined in any one of aspects 1-27, wherein thetreated solid oxide is a metal-treated chemically-modified solid oxide.

Aspect 37. The process defined in aspect 36, wherein prior to step (1)or step (I), the metal-treated chemically-modified solid oxide isproduced by a process comprising contacting any suitable solid oxide andany suitable electron-withdrawing anion and calcining (concurrentlyand/or subsequently) to form the chemically-modified solid oxide, andcontacting the chemically-modified solid oxide with any suitablemetal-containing compound.

Aspect 38. The process defined in aspect 36 or 37, wherein themetal-treated chemically-modified solid oxide comprises an alkali metal,an alkaline earth metal, a transition metal, or any combination thereof,and generally at an amount in a range from 1 to 30 wt. %, from 5 to 25wt. %, or from 6 to 18 wt. %, based on the total weight of themetal-treated chemically-modified solid oxide.

Aspect 39. The process defined in any one of aspects 36-38, wherein themetal-treated chemically-modified solid oxide comprises an alkali metal(an alkali metal-treated chemically-modified solid oxide), e.g., sodium,potassium, or cesium, as well as combinations thereof.

Aspect 40. The process defined in any one of aspects 36-38, wherein themetal-treated chemically-modified solid oxide comprises an alkalineearth metal (an alkaline earth metal-treated chemically-modified solidoxide), e.g., magnesium, calcium, or barium, as well as combinationsthereof.

Aspect 41. The process defined in any one of aspects 36-38, wherein themetal-treated chemically-modified solid oxide comprises a transitionmetal (a transition metal-treated chemically-modified solid oxide),e.g., titanium, zirconium, hafnium, tungsten, or zinc, as well ascombinations thereof.

Aspect 42. The process defined in any one of aspects 36-41, wherein thechemically-modified solid oxide comprises a solid oxide contacted withan electron-withdrawing anion, e.g., any solid oxide and anyelectron-withdrawing anion disclosed herein.

Aspect 43. The process defined in aspect 42, wherein (a) the solid oxidecomprises silica, alumina, silica-alumina, silica-coated alumina,aluminum phosphate, aluminophosphate, heteropolytungstate, titania,zirconia, magnesia, boria, zinc oxide, a mixed oxide thereof, or anymixture thereof, and (b) the electron-withdrawing anion comprisessulfate, bisulfate, fluoride, chloride, bromide, iodide, fluorosulfate,fluoroborate, phosphate, fluorophosphate, trifluoroacetate, triflate,fluorozirconate, fluorotitanate, phospho-tungstate, tungstate, or anycombination thereof.

Aspect 44. The process defined in any one of aspects 36-43, wherein thesolid oxide comprises alumina, silica-alumina, silica-coated alumina, ora mixture thereof.

Aspect 45. The process defined in any one of aspects 36-44, wherein theelectron-withdrawing anion comprises sulfate, fluoride, chloride, or anycombination thereof.

Aspect 46. The process defined in any one of aspects 36-44, wherein theelectron-withdrawing anion comprises sulfate.

Aspect 47. The process defined in any one of aspects 36-44, wherein theelectron-withdrawing anion comprises fluoride, chloride, or both.

Aspect 48. The process defined in any one of aspects 36-43, wherein thechemically-modified solid oxide comprises fluorided alumina, chloridedalumina, bromided alumina, sulfated alumina, tungstated alumina,fluorided silica-alumina, chlorided silica-alumina, bromidedsilica-alumina, sulfated silica-alumina, fluorided silica-zirconia,chlorided silica-zirconia, bromided silica-zirconia, sulfatedsilica-zirconia, fluorided silica-titania, fluorided silica-coatedalumina, fluorided-chlorided silica-coated alumina, sulfatedsilica-coated alumina, phosphated silica-coated alumina, or anycombination thereof.

Aspect 49. The process defined in any one of aspects 36-43, wherein thechemically-modified solid oxide comprises chlorided alumina, fluoridedsilica-alumina, fluorided silica-coated alumina, fluorided-chloridedsilica-coated alumina, sulfated alumina, sulfated silica-coated alumina,or a combination thereof.

Aspect 50. The process defined in any one of aspects 1-29, wherein thetreated solid oxide comprises calcined sodium carbonate, calcined sodiumbicarbonate, calcined potassium carbonate, calcined cesium carbonate, ora combination thereof.

Aspect 51. The process defined in any one of aspects 1-31, wherein thetreated solid oxide comprises sodium-treated alumina, potassium-treatedalumina, cesium-treated alumina, sodium-treated aluminophosphate, or acombination thereof.

Aspect 52. The process defined in any one of aspects 1-31, wherein thetreated solid oxide comprises magnesium-treated alumina, calcium-treatedalumina, barium-treated alumina, or a combination thereof.

Aspect 53. The process defined in any one of aspects 1-31, wherein thetreated solid oxide comprises zinc-treated alumina, zirconium-treatedalumina, sodium-tungsten-treated alumina, or a combination thereof.

Aspect 54. The process defined in any one of aspects 1-31, wherein thetreated solid oxide comprises sodium-treated chlorided alumina,sodium-treated sulfated alumina, sodium-treated tungstated alumina,sodium-treated sulfated silica-coated alumina, sodium-treated fluoridedsilica-coated alumina, sodium-treated fluorided silica-alumina,sodium-treated fluorided-chlorided silica-coated alumina, or acombination thereof.

Aspect 55. The process defined in any one of aspects 1-54, wherein thetreated solid oxide has any suitable surface area, or a surface area inany range disclosed herein, e.g., from 10 m²/g to 750 m²/g, from 20 m²/gto 500 m²/g, or from 30 m²/g to 350 m²/g.

Aspect 56. The process defined in any one of aspects 1-55, wherein thetreated solid oxide has any suitable pore volume, or a pore volume inany range disclosed herein, e.g., from 0.1 mL/g to 2.5 mL/g, from 0.1mL/g to 1.5 mL/g, or from 0.2 mL/g to 1.0 mL/g.

Aspect 57. The process defined in any one of aspects 1-56, wherein thediluent comprises any suitable non-protic solvent, or any non-proticsolvent disclosed herein.

Aspect 58. The process defined in any one of aspects 1-56, wherein thediluent comprises any suitable weakly coordinating or non-coordinatingsolvent, or any weakly coordinating or non-coordinating solventdisclosed herein.

Aspect 59. The process defined in any one of aspects 1-56, wherein thediluent comprises any suitable carbonyl-containing solvent, or anycarbonyl-containing solvent disclosed herein, e.g., ketones, esters, oramides (e.g., acetone, ethyl acetate, or N,N-dimethylformamide).

Aspect 60. The process defined in any one of aspects 1-56, wherein thediluent comprises any suitable ether solvent, or any ether solventdisclosed herein, e.g., THF, dimethyl ether, diethyl ether, or dibutylether.

Aspect 61. The process defined in any one of aspects 1-56, wherein thediluent comprises any suitable aromatic hydrocarbon solvent, or anyaromatic hydrocarbon solvent disclosed herein, e.g., benzene, xylene, ortoluene.

Aspect 62. The process defined in any one of aspects 1-56, wherein thediluent comprises any suitable halogenated aromatic hydrocarbon solvent,or any halogenated aromatic hydrocarbon solvent disclosed herein, e.g.,chlorobenzene or dichlorobenzene.

Aspect 63. The process defined in any one of aspects 1-56, wherein thediluent comprises THF, 2,5-Me₂THF, methanol, acetone, toluene,chlorobenzene, pyridine, or a combination thereof.

Aspect 64. The process defined in any one of aspects 1-63, wherein thetransition metal of the metallalactone (or of the transitionmetal-ligand complex) is a Group 8-11 transition metal.

Aspect 65. The process defined in any one of aspects 1-63, wherein thetransition metal of the metallalactone (or of the transitionmetal-ligand complex) is Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, or Au.

Aspect 66. The process defined in any one of aspects 1-63, wherein thetransition metal of the metallalactone (or of the transitionmetal-ligand complex) is Ni, Fe, or Rh.

Aspect 67. The process defined in any one of aspects 1-63, wherein themetallalactone is a nickelalactone, e.g., any suitable nickelalactone orany nickelalactone disclosed herein.

Aspect 68. The process defined in any one of aspects 1-67, wherein theligand of the metallalactone (or of the transition metal-ligand complex)is any suitable neutral electron donor group and/or Lewis base, or anyneutral electron donor group and/or Lewis base disclosed herein.

Aspect 69. The process defined in any one of aspects 1-67, wherein theligand of the metallalactone (or of the transition metal-ligand complex)is a bidentate ligand.

Aspect 70. The process defined in any one of aspects 1-69, wherein theligand of the metallalactone (or of the transition metal-ligand complex)comprises at least one of a nitrogen, phosphorus, sulfur, or oxygenheteroatom.

Aspect 71. The process defined in any one of aspects 1-69, wherein theligand of the metallalactone (or of the transition metal-ligand complex)is any suitable carbene group or any carbene group disclosed herein.

Aspect 72. The process defined in any one of aspects 1-69, wherein themetallalactone, ligand, or transition metal-ligand complex is anysuitable metallalactone, ligand, or transition metal-ligand complex, oris any metallalactone, ligand, or transition metal-ligand complexdisclosed herein.

1-20. (canceled)
 21. A process for producing an α,β-unsaturatedcarboxylic acid, or a salt thereof, the process comprising: (I)contacting a solid oxide and a transition metal-containing compound andcalcining to form a transition metal-treated solid oxide; (II)contacting (i) a transition metal-ligand complex; (ii) an olefin; (iii)carbon dioxide (CO₂); (iv) a diluent; and (v) the transitionmetal-treated solid oxide; and (III) forming the α,β-unsaturatedcarboxylic acid, or the salt thereof; wherein the transitionmetal-treated solid oxide does not have an organic basic moiety that iscovalently bound with a linking moiety to the transition metal-treatedsolid oxide; and wherein the molar yield of the α,β-unsaturatedcarboxylic acid, or the salt thereof, based on the transition metal ofthe transition metal-ligand complex, is at least 50%.
 22. The process ofclaim 21, wherein: the α,β-unsaturated carboxylic acid, or the saltthereof, comprises acrylic acid, methacrylic acid, 2-ethylacrylic acid,cinnamic acid, sodium acrylate, magnesium acrylate, sodium methacrylate,or a combination thereof; and the molar yield of the α,β-unsaturatedcarboxylic acid, or the salt thereof, based on the transition metal ofthe transition metal-ligand complex, is from 75% to 10,000%.
 23. Theprocess of claim 21, wherein: the olefin comprises ethylene; and theα,β-unsaturated carboxylic acid comprises acrylic acid.
 24. The processof claim 23, wherein the molar yield of the αβ-unsaturated carboxylicacid, or the salt thereof, based on the transition metal of thetransition metal-ligand complex, is from 75% to 10,000%.
 25. The processof claim 21, wherein the transition metal of the transition metal-ligandcomplex is a Group 8-11 transition metal, and the ligand of thetransition metal-ligand complex is a neutral electron donor group orLewis base.
 26. The process of claim 21, wherein the transitionmetal-containing compound comprises titanium, zirconium, hafnium,tungsten, zinc, or any combination thereof.
 27. The process of claim 21,wherein the solid oxide comprises alumina, titania, zirconia, magnesia,boria, calcia, zinc oxide, silica-alumina, silica-coated alumina,silica-titania, silica-zirconia, silica-magnesia, alumina-titania,alumina-zirconia, zinc-aluminate, alumina-boria, silica-boria, aluminumphosphate, aluminophosphate, aluminophosphate-silica, magnesiumaluminate, titania-zirconia, or any combination thereof.
 28. The processof claim 21, wherein: the transition metal of the transitionmetal-ligand complex is a Group 8-11 transition metal; theα,β-unsaturated carboxylic acid, or the salt thereof, comprises acrylicacid, methacrylic acid, 2-ethylacrylic acid, cinnamic acid, sodiumacrylate, magnesium acrylate, sodium methacrylate, or a combinationthereof; and the molar yield of the α,β-unsaturated carboxylic acid, orthe salt thereof, based on the transition metal of the transitionmetal-ligand complex, is from 75% to 10,000%.
 29. The process of claim28, wherein: the transition metal-containing compound comprisestitanium, zirconium, hafnium, tungsten, zinc, or any combinationthereof; and the solid oxide comprises alumina, titania, zirconia,magnesia, boria, calcia, zinc oxide, silica-alumina, silica-coatedalumina, silica-titania, silica-zirconia, silica-magnesia,alumina-titania, alumina-zirconia, zinc-aluminate, alumina-boria,silica-boria, aluminum phosphate, aluminophosphate,aluminophosphate-silica, magnesium aluminate, titania-zirconia, or anycombination thereof.
 30. The process of claim 29, wherein: the olefincomprises ethylene; and the α,β-unsaturated carboxylic acid comprisesacrylic acid.
 31. The process of claim 29, wherein: the transition metalof the transition metal-ligand complex is nickel; and the solid oxidecomprises alumina, titania, zirconia, magnesia, silica-alumina,silica-coated alumina, silica-titania, or any combination thereof.
 32. Aprocess for performing a metallalactone elimination reaction, theprocess comprising: (1) contacting a solid oxide and a transitionmetal-containing compound and calcining to form a transitionmetal-treated solid oxide; (2) contacting (a) a metallalactone; (b) adiluent; and (c) the transition metal-treated solid oxide; and (3)forming an α,β-unsaturated carboxylic acid, or a salt thereof; whereinthe transition metal-treated solid oxide does not have an organic basicmoiety that is covalently bound with a linking moiety to the transitionmetal-treated solid oxide; and wherein the molar yield of theα,β-unsaturated carboxylic acid, or the salt thereof, based on themetallalactone, is at least 5%.
 33. The process of claim 32, wherein instep (2), the metallalactone and the diluent contact a fixed bed of thetransition metal-treated solid oxide.
 34. The process of claim 32,wherein: the molar yield of the α,β-unsaturated carboxylic acid, or thesalt thereof, based on the metallalactone, is from 50% to 10,000%; themetallalactone is a nickelalactone; and the α,β-unsaturated carboxylicacid comprises acrylic acid.
 35. The process of claim 34, wherein: thesolid oxide comprises alumina, titania, zirconia, magnesia, boria,calcia, zinc oxide, silica-alumina, silica-coated alumina,silica-titania, silica-zirconia, silica-magnesia, alumina-titania,alumina-zirconia, zinc-aluminate, alumina-boria, silica-boria, aluminumphosphate, aluminophosphate, aluminophosphate-silica, magnesiumaluminate, titania-zirconia, or any combination thereof; and thetransition metal-containing compound comprises titanium, zirconium,hafnium, tungsten, zinc, or any combination thereof.
 36. The process ofclaim 32, wherein: the molar yield of the α,β-unsaturated carboxylicacid, or the salt thereof, based on the metallalactone, is from 50% to10,000%; and the α,β-unsaturated carboxylic acid, or the salt thereof,comprises acrylic acid, methacrylic acid, 2-ethylacrylic acid, cinnamicacid, sodium acrylate, magnesium acrylate, sodium methacrylate, or acombination thereof.
 37. The process of claim 36, wherein the solidoxide comprises alumina, titania, zirconia, magnesia, boria, calcia,zinc oxide, silica-alumina, silica-coated alumina, silica-titania,silica-zirconia, silica-magnesia, alumina-titania, alumina-zirconia,zinc-aluminate, alumina-boria, silica-boria, aluminum phosphate,aluminophosphate, aluminophosphate-silica, magnesium aluminate,titania-zirconia, or any combination thereof.
 38. The process of claim36, wherein the transition metal-containing compound comprises titanium,zirconium, hafnium, tungsten, zinc, or any combination thereof.
 39. Theprocess of claim 36, wherein the metallalactone is a nickelalactone. 40.The process of claim 36, wherein the solid oxide comprises alumina,titania, zirconia, magnesia, silica-alumina, silica-coated alumina,silica-titania, or any combination thereof.